synecdoche
[L. a. Gk synekdoche] /suh NEK duh kee/ (rhymes with Schenectady : )
a figure by which a more comprehensive term is used for a less comprehensive or vice versa; as whole for part or part for whole, genus for species or species for genus, etc. (compare metonymy)

metonymy
/met ON ah me/ a figure of speech in which one word or phrase is substituted for another with which it is closely associated, as in the use of Washington for the United States government or of the sword for military power

source: worthless word for the day : )