What is "hot metal typesetting"

n. any method of typesetting that involves injecting a molten metal alloy into a matrix to form a relief printing surface

In printing and typography, hot metal typesetting (also called mechanical typesetting, hot lead typesetting, hot metal, and hot type) refers to technologies for typesetting text in letterpress printing. This method injects molten type metal into a mold that has the shape of one or more glyphs. The resulting sorts and slugs are later used to press ink onto paper.