An obelus (plural, obeli) is a symbol of a line with dots above and below, , and is used to represent the division operation in mathematics. Because of that, 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 is used occasionally, mostly as a standalone symbol for the division operation itself (as on a calculator), or as an operator in elementary arithmetic. In most cases, division is now represented using other ways, often by a forward slash (/), also known as "solidus".