To draw a line over or above text.Does "over" hear refer to a crossing out action or the same as the adjective "above"? If the latter, the definition should be replaced with "synonym of overbar"
An act or instance of marking text with an overline.
Passing over a railway line.
An overline, overscore, or overbar, is a typographical feature of a horizontal line drawn immediately above the text. In old mathematical notation, an overline was called a vinculum, a notation for grouping symbols which is expressed in modern notation by parentheses, though it persists for symbols under a radical sign.