Rho
![]() | ||||||||||||||||||||||||||||||||||||||||||||||||
Greek Alpha bet | ||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
||||||||||||||||||||||||||||||||||||||||||||||||
History | ||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||
Diacritics and other symbols | ||||||||||||||||||||||||||||||||||||||||||||||||
Use in other languages | ||||||||||||||||||||||||||||||||||||||||||||||||
Related topics | ||||||||||||||||||||||||||||||||||||||||||||||||
Rho(/ˈroʊ/;uppercaseΡ,lowercaseρorϱ;Greek:ροorρω) is the seventeenth letter of theGreek Alpha bet.In the system ofGreek numeralsit has a value of 100. It is derived fromPhoenician letterres.Its uppercase form uses the sameglyph,Ρ, as the distinctLatinletterP;the two letters havedifferent Unicode encodings.
Uses
[edit]![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/df/NAMA_Alphabet_grec.jpg/220px-NAMA_Alphabet_grec.jpg)
Greek
[edit]Rho is classed as aliquid consonant(together withLambdaand sometimes the nasalsMuandNu), which has important implications formorphology.In bothAncientandModern Greek,it represents analveolar trillIPA:[r],alveolar tapIPA:[ɾ],oralveolar approximantIPA:[ɹ].
Inpolytonic orthography,a rho at the beginning of a word is written with arough breathing,equivalent toh(ῥrh), and adoublerho within a word is written with asmooth breathingover the first rho and a rough breathing over the second (ῤῥrrh). That apparently reflected anaspiratedorvoicelesspronunciation inAncient Greek,which led to the various Greek-derived English words starting withrhor containingrrh.
The name of the letter is written in Greek asῥῶ(polytonic) or ρω/ρο(monotonic).
Other Alpha bets
[edit]Letters that arose from rho include RomanRand CyrillicEr(Р).
Mathematics and science
[edit]The charactersρandϱare also conventionally used outside the Greek Alpha betical context inscienceandmathematics.
- In thephysical sciencesto represent:
- Densities:mass density,air densityorcharge density(ρ)
- Resistivity(ρ)
- Rho meson(ρ+,ρ−,ρ0)
- General quantum states
- Hammett Equation,ρ is used to represent the reaction constant, this is independent of the position and nature of the substituents of the benzene ring.
- Inmathematicsto represent:
- A length coordinate inpolar,cylindrical,spherical,andtoroidalcoordinate systems, andtoroidal and poloidalcoordinates of the Earth's magnetic field.
- Thecorrelation coefficientof a population parameter
- Thespectral radiusof a matrixdenoted as
- Theplastic ratio
- Theprime constant
- Thesensitivityto interest rates of a pricing function
- The expected return of a given policy () inreinforcement learning,denoted
- Therename operationin relational algebra
- Ineconomicsto represent the discount rate of future pence cash flows
- Inmolecular biologyto represent theRho proteinresponsible for termination of RNA synthesis. In such occasions, it is often represented asU+03F1ϱGREEK RHO SYMBOL,to avoid confusion with the Latin letterp
- Inmolecular biologyto represent theRho family of GTPases,important for cytoskeletal dynamic regulation.
- Inecologyto represent the population damping ratio where ρ = λ1 / |λ2|.
- Incomputer programming
- The lower-case rho "⍴" means reshape in theAPL programming language,and by extension also queries shape
- The lower-case rho "ρ" is used for the unaryrename operationinrelational algebra
- Instatisticsto representSpearman's rank correlation coefficient,commonly known as Spearman's rho
- Inoptionstheory to represent the rate of change of a portfolio with respect tointerest rates
Chi Rho (☧)
[edit]![](https://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Simple_Labarum2.svg/137px-Simple_Labarum2.svg.png)
The letter rho overlaid withchiforms theChi Rhosymbol, used to representJesus Christ.It was first used by EmperorConstantine the Great.A can be seen on his standard known as theLabarum.
Rho with stroke (ϼ)
[edit]The rho with a stroke through its tail is used for abbreviations involving rho, most notably inγϼforγράμμαas a unit of measurement.[1]
Character encodings
[edit]Preview | Ρ | ρ | Ῥ | ῥ | ῤ | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | GREEK CAPITAL LETTER RHO | GREEK SMALL LETTER RHO | GREEK CAPITAL LETTER RHO WITH DASIA | GREEK SMALL LETTER RHO WITH DASIA | GREEK SMALL LETTER RHO WITH PSILI | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 929 | U+03A1 | 961 | U+03C1 | 8172 | U+1FEC | 8165 | U+1FE5 | 8164 | U+1FE4 |
UTF-8 | 206 161 | CE A1 | 207 129 | CF 81 | 225 191 172 | E1 BF AC | 225 191 165 | E1 BF A5 | 225 191 164 | E1 BF A4 |
Numeric character reference | Ρ |
Ρ |
ρ |
ρ |
Ῥ |
Ῥ |
ῥ |
ῥ |
ῤ |
ῤ |
Named character reference | Ρ | ρ | ||||||||
DOS Greek | 144 | 90 | 168 | A8 | ||||||
DOS Greek-2 | 199 | C7 | 235 | EB | ||||||
Windows 1253 | 209 | D1 | 241 | F1 | ||||||
TeX | \rho |
Greek rho symbols
[edit]Preview | ϱ | ϼ | ᴩ | ᵨ | ☧ | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | GREEK RHO SYMBOL | GREEK RHO WITH STROKE SYMBOL | GREEK LETTER SMALL CAPITAL RHO | GREEK SUBSCRIPT SMALL LETTER RHO | CHI RHO | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 1009 | U+03F1 | 1020 | U+03FC | 7465 | U+1D29 | 7528 | U+1D68 | 9767 | U+2627 |
UTF-8 | 207 177 | CF B1 | 207 188 | CF BC | 225 180 169 | E1 B4 A9 | 225 181 168 | E1 B5 A8 | 226 152 167 | E2 98 A7 |
Numeric character reference | ϱ |
ϱ |
ϼ |
ϼ |
ᴩ |
ᴩ |
ᵨ |
ᵨ |
☧ |
☧ |
Named character reference | ϱ, ϱ | |||||||||
TeX | \varrho |
Coptic ro
[edit]Preview | Ⲣ | ⲣ | ⳩ | |||
---|---|---|---|---|---|---|
Unicode name | COPTIC CAPITAL LETTER RO | COPTIC SMALL LETTER RO | COPTIC SYMBOL CHI RHO | |||
Encodings | decimal | hex | dec | hex | dec | hex |
Unicode | 11426 | U+2CA2 | 11427 | U+2CA3 | 11497 | U+2CE9 |
UTF-8 | 226 178 162 | E2 B2 A2 | 226 178 163 | E2 B2 A3 | 226 179 169 | E2 B3 A9 |
Numeric character reference | Ⲣ |
Ⲣ |
ⲣ |
ⲣ |
⳩ |
⳩ |
Functional symbol
[edit]Preview | ⍴ | |
---|---|---|
Unicode name | APL FUNCTIONAL SYMBOL RHO | |
Encodings | decimal | hex |
Unicode | 9076 | U+2374 |
UTF-8 | 226 141 180 | E2 8D B4 |
Numeric character reference | ⍴ |
⍴ |
Mathematical rho
[edit]Preview | 𝚸 | 𝛒 | 𝛠 | 𝛲 | 𝜌 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL BOLD CAPITAL RHO |
MATHEMATICAL BOLD SMALL RHO |
MATHEMATICAL BOLD RHO SYMBOL |
MATHEMATICAL ITALIC CAPITAL RHO |
MATHEMATICAL ITALIC SMALL RHO | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 120504 | U+1D6B8 | 120530 | U+1D6D2 | 120544 | U+1D6E0 | 120562 | U+1D6F2 | 120588 | U+1D70C |
UTF-8 | 240 157 154 184 | F0 9D 9A B8 | 240 157 155 146 | F0 9D 9B 92 | 240 157 155 160 | F0 9D 9B A0 | 240 157 155 178 | F0 9D 9B B2 | 240 157 156 140 | F0 9D 9C 8C |
UTF-16 | 55349 57016 | D835 DEB8 | 55349 57042 | D835 DED2 | 55349 57056 | D835 DEE0 | 55349 57074 | D835 DEF2 | 55349 57100 | D835 DF0C |
Numeric character reference | 𝚸 |
𝚸 |
𝛒 |
𝛒 |
𝛠 |
𝛠 |
𝛲 |
𝛲 |
𝜌 |
𝜌 |
Preview | 𝜚 | 𝜬 | 𝝆 | 𝝔 | 𝝦 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL ITALIC RHO SYMBOL |
MATHEMATICAL BOLD ITALIC CAPITAL RHO |
MATHEMATICAL BOLD ITALIC SMALL RHO |
MATHEMATICAL BOLD ITALIC RHO SYMBOL |
MATHEMATICAL SANS-SERIF BOLD CAPITAL RHO | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 120602 | U+1D71A | 120620 | U+1D72C | 120646 | U+1D746 | 120660 | U+1D754 | 120678 | U+1D766 |
UTF-8 | 240 157 156 154 | F0 9D 9C 9A | 240 157 156 172 | F0 9D 9C AC | 240 157 157 134 | F0 9D 9D 86 | 240 157 157 148 | F0 9D 9D 94 | 240 157 157 166 | F0 9D 9D A6 |
UTF-16 | 55349 57114 | D835 DF1A | 55349 57132 | D835 DF2C | 55349 57158 | D835 DF46 | 55349 57172 | D835 DF54 | 55349 57190 | D835 DF66 |
Numeric character reference | 𝜚 |
𝜚 |
𝜬 |
𝜬 |
𝝆 |
𝝆 |
𝝔 |
𝝔 |
𝝦 |
𝝦 |
Preview | 𝞀 | 𝞎 | 𝞠 | 𝞺 | 𝟈 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL SANS-SERIF BOLD SMALL RHO |
MATHEMATICAL SANS-SERIF BOLD RHO SYMBOL |
MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL RHO |
MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL RHO |
MATHEMATICAL SANS-SERIF BOLD ITALIC RHO SYMBOL | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 120704 | U+1D780 | 120718 | U+1D78E | 120736 | U+1D7A0 | 120762 | U+1D7BA | 120776 | U+1D7C8 |
UTF-8 | 240 157 158 128 | F0 9D 9E 80 | 240 157 158 142 | F0 9D 9E 8E | 240 157 158 160 | F0 9D 9E A0 | 240 157 158 186 | F0 9D 9E BA | 240 157 159 136 | F0 9D 9F 88 |
UTF-16 | 55349 57216 | D835 DF80 | 55349 57230 | D835 DF8E | 55349 57248 | D835 DFA0 | 55349 57274 | D835 DFBA | 55349 57288 | D835 DFC8 |
Numeric character reference | 𝞀 |
𝞀 |
𝞎 |
𝞎 |
𝞠 |
𝞠 |
𝞺 |
𝞺 |
𝟈 |
𝟈 |
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.
See also
[edit]References
[edit]- ^Paul of Aeginaexplains conventional usage in the last chapter of Book VII on weights and measures and uses it throughout his work.
- ^Unicode Code Charts:Greek and Coptic (Range: 0370-03FF)