- The word “obelus” is also an alternative name for the dagger
A dagger is a typographical symbol or glyph. It is also called a cross, obelos, or obelus...
() symbol.
An
obelus (
÷) (plural,
obeli) is a symbol consisting of a short line with dots above and below. It is mainly used to represent the mathematical operation of
divisionright|thumb|200px|In mathematics, especially in elementary arithmetic, division is the arithmetic operation that is the inverse of multiplication...
. It is therefore also known as a
division sign.
The word "obelus" comes from the
GreekGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
word for a sharpened stick, spit, or pointed pillar.
- The word “obelus” is also an alternative name for the dagger
A dagger is a typographical symbol or glyph. It is also called a cross, obelos, or obelus...
() symbol.
An
obelus (
÷) (plural,
obeli) is a symbol consisting of a short line with dots above and below. It is mainly used to represent the mathematical operation of
divisionright|thumb|200px|In mathematics, especially in elementary arithmetic, division is the arithmetic operation that is the inverse of multiplication...
. It is therefore also known as a
division sign.
History
The word "obelus" comes from the
GreekGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
word for a sharpened stick, spit, or pointed pillar. This is the same root as that of the word "
obeliskAn obelisk is a tall, narrow, four-sided, tapering monument which ends in a pyramid-like shape at the top...
". Originally this sign (or a plain line) was
used in ancient manuscripts to mark passagesObelism is the practice of annotating manuscripts with marks set in the margins. Modern obelisms are used by editors blue-penciling a manuscript or typescript...
that were suspected of being corrupted or spurious.
The obelus, invented by Aristarchus to mark suspected passages in Homer, is frequent in MSS. [i.e. manuscriptA manuscript is a recording of information that has been manually created by someone or some people, such as a hand-written letter, as opposed to being printed or reproduced some other way...
s] of the Gospel to mark just those sections, like the Pericope in John, which modern editors reject. The first corrector of א, probably the contemporary διορθωτής, was at pains to enclose in brackets and mark with dots for deletion two famous passages in Luke written by the original scribe which, being absent from B W 579 and the Egyptian versions, we infer were not accepted in the text at that time dominant in Alexandria, viz. the incident of the "Bloody Sweat" in Gethsemane (Lk.xxi.43 f.) and the saying "Father forgive them" (Lk.xi.34).
The obelus was first used as a symbol for division in 1659 in the
algebraAlgebra is the branch of mathematics concerning the study of the rules of operations and the things which can be constructed from them, including terms, polynomials, equations and algebraic structures...
book
Teutsche Algebra by
Johann RahnJohann Rahn was a Swiss mathematician who is credited with the first use of the division symbol, ÷ and the therefore sign, ∴. The symbol is used in Teutsche Algebra, published in 1659.-References:...
. Some think that
John PellJohn Pell , was an English mathematician.-Early life:He was born at Southwick in Sussex. He was educated at Steyning Grammar School, and entered Trinity College, Cambridge, at the age of thirteen. During his university career he became an accomplished linguist, and even before he took his B.A...
, who edited the book, may have been responsible for this use of the symbol. The obelus had been used by some writers to represent subtraction, and that usage continued in some parts of Europe (including
NorwayNorway , officially the Kingdom of Norway, is a country in Northern Europe occupying the western portion of the Scandinavian Peninsula, as well as Jan Mayen and the Arctic archipelago of Svalbard under the Spitsbergen Treaty...
and, until fairly recently,
DenmarkDenmark is a Scandinavian country in Northern Europe and the senior member of the Kingdom of Denmark. It is the southernmost of the Nordic countries; southwest of Sweden and south of Norway, and it is bordered to the south by Germany. Denmark borders both the Baltic and the North Sea...
).
UnicodeUnicode is a computing industry standard allowing computers to consistently represent and manipulate text expressed in most of the world's writing systems...
has a related character, ⁒, called "commercial minus sign", located at U+2052 (HTML
&x2052;).
Uses
The obelus was used occasionally in
Polish languagePolish is a West Slavic language and the official language of Poland. Its written standard is the Polish alphabet which corresponds basically to the Latin alphabet with a few additions...
typography to represent ranges (such as the range
1÷10), although this usage has been mostly discontinued. As of 2007, it was also used to indicate a range in
ItalianItalian is a Romance language spoken by about 60 million people in Italy, and by a total of around 70 million in the world. In Switzerland, Italian is one of four official languages. It is also the official language of San Marino, as well as the primary language of Vatican City...
documents and in English translations from Italian documents (for example,
40% ÷ 50% would indicate 40 percent to 50 percent).
The obelus is used primarily as a symbol for division (as on a
calculatorA calculator is a device that is used for performing mathematical calculations. It differs from a computer by having a limited problem solving ability and an interface optimized for interactive calculation rather than programming...
) and as an operator in elementary
arithmeticArithmetic or arithmetics is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple day-to-day counting to advanced science and business calculations, such as addition, subtraction, multiplication and division...
. Division is also signified in other ways — usually by writing the operands one above the other and separated by a line, or on the same line separated by a
solidusThe solidus is a punctuation mark that is found on most standard keyboards. It may also be called a shilling mark or in-line fraction bar or a forward-slash. Its Unicode encoding is U+2044....
or
slashThe American English slash is a punctuation mark. It is variously termed stroke , slash, virgule, diagonal, forward slash, right-leaning stroke, oblique dash, slant, separatrix, scratch comma, slaok, over, slak, or whack...
.
In many non-Anglophone countries, the
colonThe colon is a punctuation mark, consisting of two equally sized dots centered on the same vertical line.-Usage:As with many other punctuation marks, the usage of colon varies among languages and, for a given language, among historical periods...
is used as a division sign: “
a divided by
b” is written as
a :
b.
On a Windows computer, the obelus is produced with
AltThe Alt key on a computer keyboard is used to change the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer...
+0247 or
AltThe Alt key on a computer keyboard is used to change the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer...
+246 on the number pad. On a Macintosh, it is produced with
OptionThe Option key is a modifier key present on Apple keyboards. It is located between the Control key and Command key on a typical Mac keyboard. For desktop keyboards, there are usually two, while a laptop may have only one to make room for the arrow keys...
+ / (Option + slash). On UNIX-based systems using
ScreenGNU Screen is a free terminal multiplexer that allows a user to access multiple separate terminal sessions inside a single terminal window or remote terminal session...
or X with a
Compose keyOn some computer systems, a compose key is a key which is designated to signal the software to interpret the next keystrokes as a combination in order to produce a character not found on the keyboard....
enabled, it can be produced by composing : (colon) and - (minus), though this is locale- and setting-dependent. It may also be input by Unicode code-point on GTK-based applications by pressing Control + Shift + U, followed by the codepoint in hexadecimal (
F7) and terminated by
return.
In the
UnicodeUnicode is a computing industry standard allowing computers to consistently represent and manipulate text expressed in most of the world's writing systems...
character set, the obelus is known as the “division sign” and has the code point U+00F7. In
HTMLHTML, which stands for Hyper Text Markup Language, is the predominant markup language for web pages. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists etc as well as for links, quotes, and other items. It allows images...
, it can be
encodedHTML has been in use since 1991, but HTML 4.0 was the first standardized version where international characters were given reasonably complete treatment...
as
÷ or
÷ (at
HTML level 3.2), or as
÷.
External links