pars pro toto (part for the whole) is a figure of speech in which a part of an object/ concept or a place is used / named to represent it in its entirety.
e.g. save your skin, mouths to feed, earn my bread and butter,
England for UK
totum pro parte, on the contrary, is a metonymy, in which the whole is named for a part.
e.g. America for United States, ‘can I get you a drink?’ ‘where are you going for the summer (read: summer holidays not the entire season)?’
