synecdoche

noun

a figure of speech in which a part is used for a whole, an individual for a class, a material for a thing, or the reverse of any of these (Ex.: bread for food, the army for a soldier, or copper for a penny)

Etymology: LME, altered (infl. by L) < synodoche < ML sinodoche, for L synecdoche < Gr synekdochē, lit., a receiving together < synekdechesthai, to receive together < syn-, together + ekdechesthai, to receive < ek-, from + dechesthai, to receive < IE base *de- > decent