The figure of speech synecdoche, the use of a term to refer to something more specific or more general, is a useful device for adding creative spice to your writing. Synecdoche falls into two categories, microcosm and macrocosm.
We employ microcosm synecdoche when referring to someone or something specific to mean what it represents in general, as in "They're no Einsteins" as a stand-in for geniuses, or "The houses in that neighborhood are Hearst Castles" to mean mansions.
Alternatively, we use macrocosm synecdoche when referring to someone or something in general to mean what it represents specifically, as in "New Yorkers run in Central Park year round" to mean just that select group of people who run in Central Park no matter where they're from, or "the United States declared war" to mean only the United States Congress declared war.
You probably use synecdoche in everyday conversation more than you think, but once you do begin to think about it, you'll get more creative with this valuable literary device.
