lever (n.) Look up lever at Dictionary.com
"simple machine consisting of a rigid piece acted upon at different points by two forces," c. 1300, from Old French levier (12c.) "a lifter, a lever, crowbar," agent noun from lever "to raise" (10c.), from Latin levare "to raise," from levis "light" in weight, "not heavy," also, of motion, "quick, rapid, nimble;" of food, "easy to digest;" figuratively "slight, trifling, unimportant; fickle, inconsistent;" of punishments, etc., "not severe."

This is from PIE root *legwh- "light, having little weight; easy, agile, nimble" (source also of Sanskrit laghuh "quick, small;" Greek elakhys "small," elaphros "light;" Old Church Slavonic liguku, Lithuanian lengvas "light;" Old Irish laigiu "smaller, worse;" Gothic leihts, Old English leoht "light" (adj.)). As a verb, 1856, from the noun.