Anobelus(plural:obelusesorobeli) is a term incodicologyand latterly intypographythat refers to a historical annotation mark which has resolved to three modern meanings:
- Division sign÷
- Dagger†
- Commercial minus sign⁒(limited geographical area of use)
| ÷ † ⁒ ⸓ | |
|---|---|
Modern forms of the obelus | |
| InUnicode | U+00F7÷DIVISION SIGN U+2020†DAGGER U+2052⁒COMMERCIAL MINUS SIGN U+2E13⸓DOTTED OBELOS |
| Different from | |
| Different from | U+0025%PERCENT SIGN |
| Related | |
| See also | U+261E☞WHITE RIGHT POINTING INDEX |
The word "obelus" comes fromὀβελός(obelós), theAncient Greekword for a sharpened stick, spit, or pointed pillar.[1]This is the same root as that of the word 'obelisk'.[2]
In mathematics, the first symbol is mainly used inAnglophonecountries to represent the mathematical operation ofdivisionand is called an obelus.[3]In editing texts, the second symbol, also called adaggermark†is used to indicate erroneous or dubious content;[4][5]or as a reference mark orfootnoteindicator.[6]It also hasother usesin a variety of specialist contexts.
Use in text annotation
editThe modern dagger symbol originated from a variant of the obelus, originally depicted by a plain line−,or a line with one or two dots⨪÷.[7]It represented an iron roasting spit, a dart, or the sharp end of ajavelin,[8]symbolizing the skewering or cutting out of dubious matter.[9]
Originally, one of these marks (or a plain line) was used in ancient manuscripts to mark passages that were suspected of being corrupted or spurious; the practice of adding such marginal notes became known asobelism.Thedagger symbol†,also called anobelisk,[10]is derived from the obelus, and continues to be used for this purpose.
The obelus is believed to have been invented by theHomeric scholarZenodotus,as one of a system of editorial symbols. They marked questionable or corrupt words or passages in manuscripts of theHomeric epics.[9]The system was further refined by his studentAristophanes of Byzantium,who first introduced theasteriskand used a symbol resembling a⊤for an obelus; and finally by Aristophanes' student, in turn,Aristarchus,from whom they earned the name of "Aristarchian symbols".[11][12]
In some commercial and financial documents, especially in Germany and Scandinavia, a variant (U+2052⁒COMMERCIAL MINUS SIGN) is used in the margins of letters to indicate an enclosure, where the upper point is sometimes replaced with the corresponding number.[13]In Finland, the obelus (or a slight variant,) is used as a symbol for a correct response (alongside thecheck mark,✓,which is used for anincorrectresponse).[14][15]
In the 7.0 release of Unicode,U+2E13⸓DOTTED OBELOSwas one ofa groupof "Ancient Greek textual symbols" that were added to the specification (in the blockSupplemental Punctuation).[16]
In mathematics
edit
The form of the obelus as a horizontal line with a dot above and a dot below,÷,was first used as a symbol fordivisionby theSwissmathematicianJohann Rahnin his bookTeutsche Algebrain 1659. This gave rise to the modern mathematical symbol÷,used in anglophone countries as adivision sign.[17][18]This usage, though widespread in Anglophone countries, is neither universal nor recommended: theISO 80000-2standard formathematical notationrecommends only thesolidus/orfraction barfor division, or thecolon:forratios;it says that÷"should not be used" for division.[19]The ambiguity of mathematical expressions that involve theobelus and implicit multiplicationhas become a subject of Internet memes.
This form of the obelus was also occasionally used as a mathematical symbol forsubtractionin Northern Europe; such usage continued in some parts of Europe (includingNorwayand, until fairly recently,Denmark).[20]InItaly,PolandandRussia,this notation is sometimes used inengineeringto denote arange of values.[21]
In some commercial and financial documents, especially in Germany and Scandinavia, another form of the obelus – thecommercial minus sign– is used to signify a negative remainder of a division operation.[22][14]
See also
edit- Manicule– Symbol depicting a pointing finger (☞) used for obelism.
- Obelisk– Tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top
- Obelix– Cartoon character in the French comic book series Asterix
- Obol (coin)– Unit of ancient Greek coinage
- List of typographical symbols and punctuation marks
References
edit- ^R. E. Allen, ed. (1993).The Concise Oxford Dictionary.p. 817.
- ^R. E. Allen, ed. (1993).The Concise Oxford Dictionary.p. 816.
- ^Weisstein, Eric W."Division".mathworld.wolfram.com.Retrieved2020-08-26.
- ^Wolf, Friedrich August (2014).Prolegomena to Homer, 1795.Translated by Anthony Graton. Princeton University Press. pp. 63, 202–203.ISBN9781400857692.
- ^Howatson, M. C. (2013). "Obelos".The Oxford Companion to Classical Literature.Oxford University Press.ISBN9780191073014.
- ^The Chambers Dictionary.Allied Publishers. 1998. p. 1117.ISBN9788186062258.
- ^Merriam-Webster's collegiate dictionary.Merriam-Webster, Inc. 2003. p.855.ISBN978-0-87779-809-5.
obelos.
- ^William Harrison Ainsworth, ed. (1862).The New monthly magazine.Vol. 125. Chapman and Hall. p. 1.
- ^abHarold P. Scanlin (1998)."A New Edition of Origen's Hexapla: How It Might Be Done".In Alison Salvesen (ed.).Origen's Hexapla and fragments: papers presented at the Rich Seminar on the Hexapla, Oxford Centre for Hebrew and Jewish Studies, 25th-3rd August.Mohr Siebeck. p. 439.ISBN978-3-16-146575-8.
- ^"Dagger (8)".The Oxford English Dictionary (D–E.1933. p.7.
- ^Paul D. Wegner (2006).A student's guide to textual criticism of the Bible.InterVarsity Press. p. 194.ISBN978-0-19-814747-3.
- ^George Maximilian Anthony Grube (1965).The Greek and Roman critics.Hackett Publishing. p. 128.ISBN978-0-87220-310-5.
- ^"Writing Systems and Punctuation".The Unicode® Standard, Version 10.0(PDF).Mountain View, CA: The Unicode Consortium. 2017.ISBN978-1-936213-16-0.
- ^abLeif Halvard Silli."Commercial minus as italic variant of division sign in German and Scandinavian context".Unicode.org.Archived fromthe originalon 2019-06-14.Retrieved2020-04-04.
- ^"6. Writing Systems and Punctuation".The Unicode® Standard: Version 10.0 – Core Specification(PDF).Unicode Consortium. June 2017. p. 280, Commercial minus.
- ^"Supplemental Punctuation"(PDF).Unicode Consortium.2014.
- ^"Math Words".Math Words Alphabetical Index. p. 7. Archived fromthe originalon August 7, 2011.RetrievedAugust 26,2011.
- ^"Division".www.mathsisfun.com.Retrieved2020-08-26.
- ^ISO 80000-2,Section 9 "Operations", 2-9.6
- ^Cajori, Florian(1993),A history of mathematical notations (two volumes bound as one),Dover, pp. 242, 270–271,ISBN9780486677668.Reprint of 1928 edition.
- ^"6. Writing Systems and Punctuation".The Unicode® Standard: Version 10.0 – Core Specification(PDF).Unicode Consortium. June 2017. p. 280, Obelus.
- ^Johann Philipp Schellenberg (1825).Kaufmännische Arithmetik oder allgemeines Rechenbuch für Banquiers, Kaufleute, Manufakturisten, Fabrikanten und deren Zöglinge[Commercial arithmetic or general arithmetic book for bankers, merchants, manufacturers, craftsmen and their pupils] (in German). p. 213.
