synecdoche

n. [ L. synecdoche, Gr. synekdochh`, fr. to receive jointly; sy`n with + &unr_; to receive; &unr_; out + &unr_; to receive. ] (Rhet.) A figure or trope by which a part of a thing is put for the whole (as, fifty sail for fifty ships), or the whole for a part (as, the smiling year for spring), the species for the genus (as, cutthroat for assassin), the genus for the species (as, a creature for a man), the name of the material for the thing made, etc. Bain. [ 1913 Webster ]