A
lever ( or ) is a
machine consisting of a
beam or rigid rod pivoted at a fixed
hinge, or . A lever is a rigid body capable of rotating on a point on itself. It is one of the six
simple machines identified by Renaissance scientists. The word entered
English about 1300 from
Old French, in which the word was
levier. This sprang from the stem of the verb
lever, meaning "to raise". The verb, in turn, goes back to the
Latin levare, itself from the adjective
levis, meaning "light" (as in "not heavy"). The word's ultimate origin is the
Proto-Indo-European (PIE) stem
legwh-, meaning "light", "easy" or "nimble", among other things. The PIE stem also gave rise to the English word "light". A lever amplifies an input force to provide a greater output force, which is said to provide
leverage. The ratio of the output force to the input force is the
mechanical advantage of the lever.