8

This article is about the number. For the years, see8 BCandAD 8.For other uses, see8 (disambiguation)andNumber Eight (disambiguation).

"8th" redirects here. For other uses, seeEighth (disambiguation).

← 7 8 9 →
−10123456789→ List of numbers Integers ←0102030405060708090→
Cardinal	eight
Ordinal	8th (eighth)
Numeral system	octal
Factorization	23
Divisors	1, 2, 4, 8
Greek numeral	Η´
Roman numeral	VIII, viii
Greekprefix	octa-/oct-
Latinprefix	octo-/oct-
Binary	10002
Ternary	223
Senary	126
Octal	108
Duodecimal	812
Hexadecimal	816
Greek	η (or Η)
Arabic,Kurdish,Persian,Sindhi,Urdu	٨
Amharic	፰
Bengali	৮
Chinese numeral	Tám, bát
Devanāgarī	८
Kannada	೮
Malayalam	൮
Telugu	౮
Tamil	௮
Hebrew	ח
Khmer	៨
Thai	๘
Armenian	Ը ը
Babylonian numeral	𒐜
Egyptian hieroglyph	𓐁
Morse code	_ _ _..

8(eight) is thenatural numberfollowing7and preceding9.

Etymology

Englisheight,from Old Englisheahta,æhta,Proto-Germanic*ahtois a direct continuation ofProto-Indo-European*oḱtṓ(w)-,and as such cognate with Greekὀκτώand Latinocto-,both of which stems are reflected by the English prefixoct(o)-,as in the ordinal adjectiveoctavaloroctavary,the distributive adjective isoctonary. The adjectiveoctuple(Latinoctu-plus) may also be used as a noun, meaning "a set of eight items"; the diminutiveoctupletis mostly used to refer to eight siblings delivered in one birth.

TheSemitic numeralis based on a root*θmn-,whence Akkadiansmn-,Arabicṯmn-,Hebrewšmn-etc. TheChinese numeral,writtenTám(Mandarin:bā;Cantonese:baat), is fromOld Chinese*priāt-,ultimately from Sino-Tibetanb-r-gyatorb-g-ryatwhich also yielded Tibetanbrgyat.

It has been argued that, as thecardinal number7is the highest number of items that can universally becognitively processedas a single set, the etymology of the numeraleightmight be the first to be considered composite, either as "twice four" or as "two short of ten", or similar. TheTurkicwords for "eight" are from aProto-Turkicstem*sekiz,which has been suggested as originating as a negation ofeki"two", as in "without two fingers" (i.e., "two short of ten; two fingers are not being held up" ); this same principle is found inFinnic*kakte-ksa,which conveys a meaning of "two before (ten)". The Proto-Indo-European reconstruction*oḱtṓ(w)-itself has been argued as representing an old dual, which would correspond to an original meaning of "twice four". Proponents of this "quaternary hypothesis" adduce the numeral9,which might be built on the stemnew-,meaning "new" (indicating the beginning of a "new set of numerals" after having counted to eight).

Evolution of the Arabic digit

Evolution of the numeral 8 from the Indians to the Europeans

The modern digit 8, like all modernArabic numeralsother than zero, originates with theBrahmi numerals. The Brahmi digit foreightby the 1st century was written in one stroke as a curve └┐ looking like an uppercase H with the bottom half of the left line and the upper half of the right line removed. However, the digit for eight used in India in the early centuries of the Common Era developed considerable graphic variation, and in some cases took the shape of a single wedge, which was adopted into the Perso-Arabic tradition as٨(and also gave rise to the later Devanagari form८); the alternative curved glyph also existed as a variant in Perso-Arabic tradition, where it came to look similar to our digit 5.

The digits as used inAl-Andalusby the 10th century were a distinctive western variant of the glyphs used in the Arabic-speaking world, known asghubārnumerals (ghubārtranslating to "sand table"). In these digits, the line of the5-like glyph used in Indian manuscripts for eight came to be formed in ghubār as a closed loop, which was the8-shape that became adopted into European use in the 10th century.

Just as in most moderntypefaces,in typefaces withtext figuresthe character for the digit 8 usually has anascender,as, for example, in.

Theinfinity symbol∞, described as a "sideways figure eight", is unrelated to the digit 8 in origin; it is first used (in the mathematical meaning "infinity" ) in the 17th century, and it may be derived from theRoman numeralfor "one thousand" CIƆ, or alternatively from the final Greek letter,ω.

Mathematics

Eightis the thirdcomposite number,lying between the fourth prime number (7) and the fourth composite number (9). 8 is the first non-unitary cubeprimeof the formp³.Withproper divisors1,2,and4,it is the thirdpower of two(2³). 8 is the first number which is neitherprimenorsemiprimeand the only nonzeroperfect powerthat is one less than another perfect power, byMihăilescu's Theorem.

• 8 is the first properLeyland numberof the formx^y+ y^x,where in its casexandyboth equal 2.
• 8 is the sum between the first pair oftwin-primes(3,5), and the only twin-prime sum that is not a multiple of3or12.
• 8 is the sixthFibonacci numberand the first even, non-prime Fibonacci number. It is also the only positive Fibonacci number aside from1that is aperfect cube.
• 8 is the thirdrefactorable number,as it has exactly four positive divisors, and 4 is one of them.
• 8 is the only composite number with a primealiquot sumof 7 (1 +2+4)that is part of the aliquot sequence (8, 7,1,0).
• 8 is the first number to be the aliquot sum of two numbers: the discretesemiprime10=5× 2, andsquaredprime49= 7².
• 8 is surrounded by (7,9) which multiply to equal the forty-fourthcompositenumber63,where the eighthtriangular numberand twenty-fourth composite is36.
• 8 is the number of knownprimary pseudoperfect numbers,the smallest four (2, 6,42,1806) are one less than the first four numbers inSylvester's sequence.

Sphenic numbersalways have exactly eight divisors.

Octagon

Apolygonwith eight sides is anoctagon.The sides andspanof aregular octagon,ortruncatedsquare,are in1: 1 +√2silver ratio,and itscircumscribingsquarehas a side and diagonal length ratio of1:√2;with both the silver ratio and thesquare root of twointimately interconnected throughPell numbers,where in particular the quotient of successive Pell numbers generates rational approximations for coordinates of aregular octagon.With acentral angleof 45 degrees and aninternal angleof 135 degrees, a regular octagon can fill aplane-vertexwith a regulartriangleand a regularicositetragon,as well astessellatetwo-dimensional space alongside squares in thetruncated square tiling.This tiling is one of eightArchimedean tilingsthat are semi-regular, or made of more than one type of regularpolygon,and the only tiling that can admit a regular octagon.TheAmmann–Beenker tilingis a nonperiodic tesselation ofprototilesthat feature prominent octagonalsilvereightfold symmetry, that is the two-dimensionalorthographic projectionof the four-dimensional8-8 duoprism.In number theory,figurate numbersrepresenting octagons are calledoctagonal numbers.

Cube and octahedron

Acubeis aregular polyhedronwith eightverticesthat also forms thecubic honeycomb,the only regular honeycomb in three-dimensional space.Through various truncation operations, thecubic honeycombgenerates eight otherconvex uniform honeycombsunder the cubic group${\tilde {C}}_{3}$.Theoctahedron,with eightequilateral trianglesasfaces,is thedual polyhedronto the cube and one of eightconvex deltahedra.Thestella octangula,oreight-pointed star,is the onlystellationwithoctahedral symmetry.It has eight triangular faces alongside eight vertices that forms a cubicfaceting,composed of two self-dualtetrahedrathat makes it the simplest of fiveregular compounds.Thecuboctahedron,on the other hand, is arectifiedcube or rectified octahedron, and one of only two convexquasiregular polyhedra.It contains eight equilateral triangular faces, whose firststellationis thecube-octahedron compound.There are also eightuniform polyhedron compoundsmade purely of octahedra, including the regularcompound of five octahedra,and an infinite amount of polyhedron compounds made only of octahedra astriangular antiprisms(UC₂₂andUC₂₃,withp= 3 andq= 1).

Truncated figures

Thetruncated tetrahedronis the simplest Archimedean solid, made of four triangles and four hexagons, thehexagonal prism,which classifies as anirregular octahedronandparallelohedron,is able totessellatespace as a three-dimensional analogue of thehexagon,and thegyrobifastigium,with four square faces and four triangular faces, is the onlyJohnson solidthat is able to tessellate space. Thetruncated octahedron,also a parallelohedron, is thepermutohedronof order four, with eight hexagonal faces alongside six squares is likewise the onlyArchimedean solidthat can generate ahoneycombon its own.

Polychora

Atesseractor8-cell is thefour-dimensionalanalogue of thecube.It is one of sixregularpolychora,with a total of eight cubicalcells,hence its name. Its dual figure is the analogue of theoctahedron,with twice the amount of cells and simply termed the16-cell,that is theorthonormal basisof vectors in four dimensions. Whereas atesseractic honeycombis self-dual, a16-cell honeycombis dual to a24-cell honeycombthat is made of24-cells.The 24-cell is also regular, and made purely of octahedra whose vertex arrangement represents theringofHurwitz integral quaternions.Both the tesseract and the 16-cell can fit inside a 24-cell, and in a 24-cell honeycomb, eight 24-cells meet at a vertex. Also, thePetrie polygonof the tesseract and the 16-cell is a regular octagon.

The octonions

Theoctonionsare ahypercomplexnormed division algebrathat are an extension of thecomplex numbers.They arerealizedin eight dimensions, where they have anisotopy groupover the real numbers that isspin groupSpin(8), the unique such group that exhibits a phenomenon oftriality.As adouble coverofspecial orthogonal groupSO(8), Spin(8) contains thespecial orthogonalLie algebra D₄as itsDynkin diagram,whose order-threeouter automorphismisisomorphicto thesymmetric groupS₃,giving rise to its triality. Over finite fields, the eight-dimensionalSteinberg group³D₄(q³)issimple,and one of sixteen such groups in the classification offinite simple groups.As is Lie algebraE₈,whose complex form in248dimensions is the largest of fiveexceptional Lie algebrasthat includeE₇andE₆,which areheldinside E₈.The smallest such algebra isG₂,that is theautomorphism groupof the octonions. Inmathematical physics,special unitary groupSO(3) has an eight-dimensionaladjoint representationwhose colors are ascribedgauge symmetriesthat represent thevectorsof the eightgluonsin theStandard Model.

The number 8 is involved with a number of interesting mathematical phenomena related to the notion ofBott periodicity.If$O(\infty )$is the direct limit of the inclusions of real orthogonal groups$O(1)\hookrightarrow O(2)\hookrightarrow \ldots \hookrightarrow O(k)\hookrightarrow \ldots$,the following holds:

$\pi _{k+8}(O(\infty ))\cong \pi _{k}(O(\infty ))$.

Clifford algebrasalso display a periodicity of 8.For example, the algebraCl(p+ 8,q) is isomorphic to the algebra of 16 by 16 matrices with entries inCl(p,q). We also see a period of 8 in theK-theoryof spheres and in therepresentation theoryof therotation groups,the latter giving rise to the 8 by 8spinorialchessboard. All of these properties (that also tie withLorentzian geometry,andJordan algebras) are closely related to the properties of theoctonions,which occupy the highest possible dimension for anormed division algebra.

E₈

The$\mathrm {E} _{8}$latticeΓ₈is the smallest positive evenunimodular lattice.As a lattice, it holds the optimal structure for the densest packing of240spheresin eight dimensions, whose lattice points also represent theroot systemofLie groupE₈.This honeycomb arrangement is shared by a unique complex tessellation ofWitting polytopes,also with 240 vertices. EachcomplexWitting polytope is made ofHessian polyhedralcells that haveMöbius–Kantor polygonsas faces, each with eight vertices and eight complexequilateral trianglesas edges, whosePetrie polygonsform regular octagons. In general, positive even unimodular lattices only exist in dimensions proportional to eight. In the 16th dimension, there are two such lattices: Γ₈⊕ Γ₈and Γ₁₆,while in the 24th dimension there are precisely twenty-four such lattices that are called theNiemeier lattices,the most important being theLeech lattice,which can be constructed using the octonions as well as with three copies of thering of icosiansthat are isomorphic to the$\mathrm {E} _{8}$lattice.The order of the smallest non-abelian group all of whose subgroups are normal is 8.

Vertex-transitivesemiregular polytopeswhosefacetsarefiniteexist up through the 8th dimension. In thethird dimension,they include theArchimedean solidsand the infinite family of uniformprismsandantiprisms,while in thefourth dimension,only therectified 5-cell,therectified 600-cell,and thesnub 24-cellare semiregular polytopes. For dimensionsfivethrough eight, thedemipenteractand thek₂₁polytopes2₂₁,3₂₁,and4₂₁are the only semiregular (Gosset) polytopes. Collectively, the k₂₁family of polytopes contains eight figures that are rooted in thetriangular prism,which is the simplest semiregular polytope that is made of three cubes and two equilateral triangles. It also includes one of only three semiregularEuclideanhoneycombs: theaffine5₂₁honeycomb that represents the arrangement of vertices of the eight-dimensional$\mathrm {E} _{8}$lattice,and made of 4₂₁facets.The culminating figure is the ninth-dimensional6₂₁honeycomb, which is the only affine semiregularparacompacthyperbolichoneycomb with infinite facets andvertex figuresin the k₂₁family. There are no other finite semiregular polytopes or honeycombs in dimensionsn> 8.

Finite simple groups

In the classification of sporadic groups, thethird generationconsists of eight groups, four of which arecentralizersof$\mathrm {F_{1}}$(itself the largest group of this generation), with another threetranspositionsofFischer group$\mathrm {F_{3+}}$.8is thedifferencebetween53and61,which are the two smallest prime numbers that do not divide the order of anysporadic group.The largestsupersingular primethat divides theorderof$\mathrm {F_{1}}$is71,which is the eighth self-convolution of Fibonacci numbers (where744,which is essential toMoonshine theory,is the twelfth).While only two sporadic groups have eight prime factors in their order (Lyons group$\mathrm {Ly}$and Fischer group$\mathrm {Fi_{23}}$),Mathieu group$\mathrm {M_{23}}$holds a semi-presentation whoseorderis equal to$o{\bigl (}(ab)^{2}(abab^{2})^{2}ab^{2}{\bigr )}=8$.

List of basic calculations

Multiplication	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
8 ×x	8	16	24	32	40	48	56	64	72	80	88	96	104	112	120

Division	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15
8 ÷x	8	4	2.6	2	1.6	1.3	1.142857	1	0.8	0.8		0.72	0.6	0.615384	0.571428	0.53
x÷ 8	0.125	0.25	0.375	0.5	0.625	0.75	0.875	1	1.125	1.25		1.375	1.5	1.625	1.75	1.875

Exponentiation	1	2	3	4	5	6	7	8	9	10		11	12	13
8x	8	64	512	4096	32768	262144	2097152	16777216	134217728	1073741824		8589934592	68719476736	549755813888
x8	1	256	6561	65536	390625	1679616	5764801	16777216	43046721	100000000		214358881	429981696	815730721

In other bases

A number is divisible by 8 if its last three digits, when written indecimal,are also divisible by 8, or its last three digits are 0 when written inbinary.

8 is the base of theoctalnumber system, which is mostly used withcomputers.In octal, one digit represents threebits.In modern computers, abyteis a grouping of eight bits, also called anoctet.

In science

Physics

• In nuclear physics, the secondmagic number.
• Inparticle physics,theeightfold wayis used to classify sub-atomic particles.
• Instatistical mechanics,theeight-vertex modelhas 8 possible configurations of arrows at each vertex.

Astronomy

• Messier objectM8,a magnitude 5.0nebulain theconstellationofSagittarius.
• TheNew General CatalogueobjectNGC 8,a double star in the constellationPegasus.
• Since the demotion ofPlutoto adwarf planeton 24 August 2006, in ourSolar System,eight of the bodies orbiting the Sun are considered to beplanets.

Chemistry

• Theatomic numberofoxygen.
• The most stable allotrope of asulfurmolecule is made of eight sulfur atoms arranged in a rhombic form.
• The maximum number of electrons that can occupy avalence shell(except for transitional elements), see theoctet rule.
• The red pigmentlycopeneconsists of eightisopreneunits.

Geology

• Adisphenoidcrystal is bounded by eight scalene triangles arranged in pairs. A ditetragonal prism in thetetragonal crystal systemhas eight similar faces whose alternate interfacial angles only are equal.

Biology

• Allspiders,and more generally allarachnids,have eight legs.Orb-weaver spidersof the cosmopolitan family Areneidae have eight similar eyes.
• Theoctopusand its cephalopod relatives in genusArgonautahave eight arms (tentacles).
• Compound coelenterates of the subclass or orderAlcyonariahave polyps with eight-branched tentacles and eight septa.
• Sea anemones of genusEdwardsiahave eightmesenteries.
• Animals of phylumCtenophoraswim by means of eight meridional bands of transverse ciliated plates, each plate representing a row of large modified cilia.
• Theeight-spotted forester(genusAlypia,familyZygaenidae) is a diurnal moth having black wings with brilliant white spots.
• Theascusin fungi of the classAscomycetes,following nuclear fusion, bears within it typically eight ascospores.
• Herbs of genusCoreopsis(tickseed) have showy flower heads with involucral bracts in two distinct series of eight each.
• In humanadult dentitionthere are eight teeth in each quadrant.The eighth tooth is the so-calledwisdom tooth.
• There are eightcervical nerveson each side in man and most mammals.

Psychology

• There are eightJungian cognitive functions,according to theMBTImodels byJohn BeebeandLinda Berens.
• Timothy Learyidentified ahierarchy of eight levels of consciousness.

In technology

NATO signal flagfor 8

• Abyteis eightbits.
• Many (mostly historic) computer architectures are eight-bit, among them theNintendo Entertainment System.
• Standard-8andSuper-8are 8 mmfilm formats.
• Video8, Hi8 and Digital8 are related8 mm video formats.
• On most phones, the 8 key is associated with the lettersT,U,andV,but on theBlackBerry Pearlit is the key forBandN.
• An eight may refer to an eight-cylinder engine or automobile.AV8 engineis aninternal combustion enginewith eight cylinders configured in two banks (rows) of four forming a "V" when seen from the end.
• Afigure-eight knot(so named for its configuration) is a kind ofstopper knot.
• The number eight written in parentheses is the code for the musical note inWindows Live Messenger.
• In aseven-segment display,when an 8 is illuminated, all the display bulbs are on.

In measurement

• TheSI prefixfor 1000⁸is yotta (Y), and for its reciprocal, yocto (y).
• In liquid measurement (United States customary units), there are eightfluid ouncesin acup,eightpintsin agallonand eighttablespoonfulsin agill.
• There are eightfurlongsin a mile.
• The clove, an oldEnglish unitof weight, was equal to eight pounds when measuring cheese.
• An eight may be an article of clothing of the eighthsize.
• Force eight is the firstwindstrength attributed to agaleon theBeaufort scalewhen announced on aShipping Forecast.

In culture

Currency

• Sailors and civilians alike from the 1500s onward referred to evenly divided parts of theSpanish dollaras "pieces of eight", or "bits".

Architecture

• Various types of buildings are usually eight-sided (octagonal), such as single-roomedgazebosand multi-roomedpagodas(descended from stupas; see religion section below).
• Eightcaulicolesrise out of the leafage in aCorinthian capital,ending in leaves that support thevolutes.

In religion, folk belief and divination

Hinduism

• As sourced from the Mahabharata, there are 8 vasus who are given elemental names:
  1. Anala or Agni (fire)
  2. Dhara or Prithvi (earth)
  3. Anila or Vayudeva (wind)
  4. Apa (water)
  5. Prabhasa or Dyauh (sky)
  6. Pratyusha
  7. Soma
  8. Dhruva
• The goddess of wealth and prosperity,Lakshmi,has eight forms known asAshta Lakshmiand worshipped as:
  "Maha-lakshmi, Dhana-lakshmi, Dhanya-lakshmi, Gaja-lakshmi,
  Santana-lakshmi, Veera-lakshmi, Vijaya-lakshmi and Vidhya-lakshmi"
• There are eightnidhi,or seats of wealth, according toHinduism.
• There are eightguardians of the directionsknown asAstha-dikpalas.
• There are eightHindumonasteries established by the saintMadhvacharyainUdupi,Indiapopularly known as theAshta Mathas of Udupi.

Buddhism

In Buddhism, the 8-spokedDharmacakrarepresents theNoble Eightfold Path.

• TheDharmacakra,aBuddhistsymbol, has eight spokes.The Buddha's principal teaching—theFour Noble Truths—ramifies as theNoble Eightfold Pathand the Buddha emphasizes the importance of the eight attainments or jhanas.
• InMahayanaBuddhism, the branches of the Eightfold Path are embodied by the Eight Great Bodhisattvas: (Manjusri,Vajrapani,Avalokiteśvara,Maitreya,Ksitigarbha,Nivaranavishkambhi,Akasagarbha,andSamantabhadra).These are later (controversially) associated with the Eight Consciousnesses according to theYogacaraschool of thought: consciousness in the five senses, thought-consciousness, self-consciousness, and unconsciousness- "consciousness" or "store-house consciousness" (alaya-vijñana). The "irreversible" state of enlightenment, at which point a Bodhisattva goes on "autopilot", is the Eight Ground orbhūmi.In general, "eight" seems to be an auspicious number for Buddhists, e.g., the "eight auspicious symbols" (the jewel-encrusted parasol; the goldfish (always shown as a pair, e.g., the glyph of Pisces); the self-replenishing amphora; the whitekamalalotus-flower; the white conch; the eternal (Celtic-style, infinitely looping) knot; the banner of imperial victory; the eight-spoked wheel that guides the ship of state, or that symbolizes the Buddha's teaching). Similarly,Buddha's birthdayfalls on the 8th day of the 4th month of theChinese calendar.

Judaism

• The religious rite ofbrit milah(commonly known ascircumcision) is held on a baby boy's eighth day of life.
• Hanukkahis an eight-day Jewish holiday that starts on the 25th day ofKislev.
• Shemini Atzeret(Hebrew:"Eighth Day of Assembly" ) is a one-day Jewish holiday immediately following the seven-day holiday ofSukkot.

Christianity

• The spiritualEighth Day,because the number 7 refers to the days of the week (which repeat themselves).
• The number ofBeatitudes.
• 1 Peter 3:20states that there were eight people onNoah's Ark.
• TheAntichristis the eighth king in theBook of Revelation.

Islam

TheoctagramRub el Hizb

• InIslam,eight is the number ofangelscarrying thethroneofAllahin heaven.
• The number of gates of heaven.
• TheoctagramRub el Hizbis often used in Islamic symbology.

Taoism

• Bagua
• Ba Xian
• Baduanjin

Other

• InWicca,there are eight Sabbats, festivals, seasons, or spokes in theWheel of the Year.
• InAncient Egyptian mythology,theOgdoadrepresents theeight primordial deities of creation.
• InScientologythere areeight dynamics of existence.
• There is also theOgdoadinGnosticism.

As a lucky number

• The number eight is considered to be alucky number in Chineseand other Asian cultures.Eight (Tám;accountingBát;pinyinbā) is considered alucky number in Chinese culturebecause it sounds like the word meaning to generate wealth (Phát (T) phát (S);Pinyin:fā). Property with the number 8 may be valued greatly by Chinese. For example, a Hong Kongnumber platewith the number 8 was sold for $640,000.The opening ceremony of theSummer Olympics in Beijingstarted at 8 seconds and 8 minutes past 8 pm (local time) on 8 August 2008.
• In Pythagoreannumerologythe number 8 represents victory, prosperity and overcoming.
• Eight(Tám,hachi, ya)is also considered a lucky number inJapan,but the reason is different from that in Chinese culture.Eight gives an idea of growing prosperous, because the letter (Tám) broadens gradually.
• The Japanese thought of eight(や,ya)as a holy number in the ancient times. The reason is less well-understood, but it is thought that it is related to the fact they used eight to express large numbers vaguely such as manyfold(やえはたえ,Yae Hatae)(literally, eightfold and twentyfold), many clouds(やくも,Yakumo)(literally, eight clouds), millions and millions of Gods(やおよろず の かみ,Yaoyorozu no Kami)(literally, eight millions of Gods), etc. It is also guessed that the ancient Japanese gave importance to pairs, so some researchers guess twice as four(よ,yo),which is also guessed to be a holy number in those times because it indicates the world (north, south, east, and west) might be considered a very holy number.
• Innumerology,8 is the number of building, and in some theories, also the number of destruction.

In astrology

• Inastrology,Scorpiois the 8thastrological signof theZodiac.
• In theMiddle Ages,8 was the number of "unmoving" stars in the sky, and symbolized the perfection of incoming planetary energy.

In music and dance

• A note played for one-eighth the duration of a whole note is called aneighth note,or quaver.
• Anoctave,the interval between twomusical noteswith the same letter name (where one has double the frequency of the other), is so called because there are eight notes between the two on a standard major or minordiatonic scale,including the notes themselves and without chromatic deviation.The ecclesiasticalmodesare ascending diatonic musical scales of eight notes or tones comprising an octave.
• There are eight notes in theoctatonic scale.
• There are eight musicians in a double quartet or anoctet.Both terms may also refer to a musical composition for eight voices or instruments.
• Caledonians is a square dance for eight, resembling thequadrille.
• Albumswith the number eight in their title include8by the Swedish bandArvingarna,8by the American rock bandIncubus,The Meaning of 8by Minnesota indie rock bandCloud Cultand8ightby Anglo-American singer-songwriterBeatie Wolfe.
• Dream Theater's eighth albumOctavariumcontains many different references to the number 8, including the number of songs and various aspects of the music and cover artwork.
• "Eight maids a-milking" is the gift on the eighth day of Christmas in the carol "The Twelve Days of Christmas".
• The8-track cartridgeis a musical recording format.
• "#8" is the stage name ofSlipknotvocalistCorey Taylor.
• "Too Many Eights" is a song by Athens, Georgia'sSupercluster.
• Eight Seconds,a Canadian musical group popular in the 1980s with their most notable song "Kiss You (When It's Dangerous)".
• "Eight Days a Week"is a #1 single for the music groupthe Beatles.
• Figure 8is the fifth studio album by singer-songwriterElliott Smith,released in the year 2000,an album released by Julia Darling in 1999,and an album released byOutasightin 2011.
• Ming Hao from the k-pop groupSeventeengoes by the name "The8".
• "8 (circle)" is the eighth song on the album22, A Millionby the American bandBon Iver.
• "8" is the eighth song on the albumWhen We All Fall Asleep, Where Do We Go?byBillie Eilish.

In film and television

• 8 Guysis a 2003 short film written and directed byDane Cook.
• 8 Man(orEightman): 1963 Japanese manga and anime superhero.
• 8 Mileis a 2002 film directed byCurtis Hanson.
• 8 mmis a 1999 film directed byJoel Schumacher.
• 8 Women(Original French title:8 femmes) is a 2001 film directed byFrançois Ozon.
• Eight Belowis a 2006 film directed byFrank Marshall.
• Eight Legged Freaksis a 2002 film directed byEllory Elkayem.
• Eight Men Outis a 1988 film directed byJohn Sayles.
• Jennifer Eight,also known asJennifer 8,is a 1992 film written and directed byBruce Robinson.
• Eight Is Enoughis an American television comedy-drama series.
• InStargate SG-1andStargate Atlantis,dialing an 8-chevron address will open awormholeto another galaxy.
• The Hateful Eightis a 2015 American western mystery film written and directed byQuentin Tarantino.
• Kate Plus 8is an American reality television show.
• Ocean's 8is an American heist comedy film directed byGary Ross.

In sports and other games

An 8-ball in pool

• Eight-ballpoolis played with a cue ball and 15 numbered balls, the black ball numbered 8 being the middle and most important one, as the winner is the player or side that legally pockets it after first pocketing its numerical group of 7 object balls (for other meanings seeEight ball (disambiguation)).
• Inchess,each side has eight pawns and the board is made of 64 squares arranged in an eight by eight lattice. Theeight queens puzzleis a challenge to arrange eight queens on the board so that none can capture any of the others.
• In the game of eights orCrazy Eights,each successive player must play a card either of the same suit or of the same rank as that played by the preceding player, or may play an eight and call for any suit. The object is to get rid of all one's cards first.
• Inassociation football,the number 8 has historically been the number of the Central Midfielder.
• InAustralian rules football,the top eight teams at the end of theAustralian Football Leagueregular season qualify for thefinals series(i.e. playoffs).
• Inbaseball:
  • Thecenter fielderis designated as number 8 for scorekeeping purposes.
  • TheMen's College World Series,the final phase of theNCAA Division I tournament,features eight teams.
• Inrugby union,the only position without a proper name is theNumber 8,a forward position.
• Inrugby league:
  • Most competitions (though not theSuper League,which uses static squad numbering) use a position-based player numbering system in which one of the two starting props wears the number 8.
  • The Australia-basedNational Rugby Leaguehas its own 8-team finals series, similar but not identical in structure to that of the Australian Football League.
• Inrowing,an "eight" refers to a sweep-oar racing boat with a crew of eight rowers plus acoxswain.
• In the2008 Games of the XXIX Olympiadheld inBeijing,the official opening was on 08/08/08 at 8:08:08 p.m.CST.
• In rock climbing, climbers frequently use thefigure-eight knotto tie into their harnesses.
• TheWomen's College World Series,the final phase of theNCAA Division I softball tournament,like its men's counterpart in baseball, features eight teams.
• Incurlingan 8-point 'Eight Ender' is a perfect end. Each team delivers 8 Stones per end.

In foods

• Nestlésells a brand of chocolates filled with peppermint-flavoured cream calledAfter Eight,referring to the time 8 p.m.
• There are eight vegetables inV8juice.

In literature

• Eights may refer tooctosyllabic,usuallyiambic,linesof verse.
• The drott-kvaett, anOld Icelandicverse, consisted of a stanza of eight regular lines.
• InTerry Pratchett'sDiscworldseries, eight is a magical numberand is considered taboo. Eight is not safe to be said by wizards on theDiscworldand is the number of Bel-Shamharoth. Also, there are eight days in a Disc week and eight colours in a Disc spectrum, the eighth one beingoctarine.
• Lewis Carroll's poemThe Hunting of the Snarkhas 8 "fits" (cantos), which is noted in the full name "The Hunting of the Snark –An Agony, in Eight Fits".
• Eight apparitions appear toMacbethin Act 4 scene 1 of Shakespeare'sMacbethas representations of the eight descendants ofBanquo.

In slang

• An "eighth" is a common measurement ofmarijuana,meaning an eighth of anounce.It is also a common unit of sale forpsilocybin mushrooms.
• Avril Lavigne's song "Sk8er Boi"uses this convention in the title.
• TheHousing Choice Voucher Program,operated by theUnited States Department of Housing and Urban Development,is commonly referred to as the Section 8 program, as this was the original section of the Act which instituted the program.
• InColombiaandVenezuela,"volverse un ocho" (meaning to tie oneself in a figure 8) refers to getting in trouble or contradicting oneself.
• In China, "8" is used in chat speak as a term for parting. This is due to the closeness in pronunciation of "8" (bā) and the English word "bye".

Other uses

• A figure 8 is the common name of ageometricshape,often used in the context of sports, such as skating.Figure-eight turns of a rope or cable around a cleat, pin, or bitt are used to belay something.

See also

• The Magical Number Seven, Plus or Minus Two
• List of highways numbered 8

External links

• The Octonions,John C. Baez