Answer: Obelus

An obelus is a symbol comprised of two dots separated by a horizontal line, ÷, familiar to most readers as the mathematical symbol for division.

The symbol’s name is derived from the Ancient Greek word for sharpened stick, spit, or pointed pillar (and shares the same root with the word “obelisk”). Historically, the symbol was not always used for division. In ancient manuscripts, it was used as an editor’s mark to indicate passages that were suspected of corruption or spurious inclusion. In slightly modified form (the dagger †), modern usage of the symbol serves to mark a footnote if an asterisk has already been used).

Later, the symbol was used to indicate subtraction and then, in the late 17th century, mathematician Johann Rahn used it in an algebra textbook (Teutsche Algebra) to indicate division. The usage caught on and outside of some areas of Europe (like Norway), the usage has shifted entirely away from subtraction and the symbol now denotes division.