Pars pro toto is Latin for "(taking) a part for the whole"; it is a kind of synecdoche. When used in a context of language it means that something is named after a part of it (or after a limited characteristic, in itself not necessarily representative for the whole). E.g. "glasses" is a "pars pro toto" name for something that consists of more than just two pieces of glass. The opposite of a pars pro toto is a totum pro parte, in which the whole is used to describe a part.

Totum pro parte is Latin for "(taking) the whole for a part"; it refers to a kind of synecdoche. When used in a context of language it means that something is named after something of which it is only a part (or only a limited characteristic, in itself not necessarily representative for the whole). A pars pro toto is the opposite of a totum pro parte in which a part is used to describe the whole.