||The English used in this article may not be easy for everybody to understand. (May 2012)|
An obelus (plural, obeli) is a symbol consisting of a line with dots above and below, , used to represent the mathematical division operation. This symbol is also known as a division sign.
The word "obelus" comes from the Greek word for a sharpened stick, spit, or pointed pillar. This is the same root as that of the word "obelisk". The obelus was first used as a symbol for division in 1659 in the algebra book Teutsche Algebra by Johann Rahn. Today the obelus remains in occasional use, primarily as a standalone symbol for the division operation itself (as on a calculator), or as an operator in elementary arithmetic. In most contexts division is now signified in other ways, often by a forward slash (/).
Other websites [change]
- Jeff Miller: Earliest Uses of Various Mathematical Symbols
- Michael Quinion: Where our arithmetic symbols come from