metonymy [mɪˈtɒnəmi] n.
1.) A trope in which one word is put for another that suggests it; as, we say, a man keeps a good table instead of good provisions; we read Virgil, that is, his poems; a man has a warm heart, that is, warm affections; a city dweller has no wheels, that is, no automobile (GNU Collaborative International Dictionary of English).
Etymology: Late Latin metonymia, from Greek metonumia : meta-, meta- + onuma, name.
"Doubtful it stood,
As two spent swimmers that do cling together
And choke their art. The merciless Macdonwald
Worthy to be a rebel, for to that
The multiplying villainies of nature
Do swarm upon himfrom the Western Isles
Of kerns and gallowglasses is supplied;
And Fortune, on his damned quarrel smiling,
Show'd like a rebel's whore. But all's too weak;
For brave Macbethwell he deserves that name
Disdaining Fortune, with his brandish'd steel,
Which smoked with bloody execution,
Like Valor's minion carved out his passage
Till he faced the slave,
Which ne'er shook hands, nor bade farewell to him,
Till he unseam'd him from the nave to the chaps,
And fix'd his head upon our battlements" (The Tragedy of Macbeth, William Shakespeare, ~1605).
I've decided to start a regular feature: I'll be defining rhetorical terms every Sunday, until we know them all. The main difference is that I'll be providing examples of the rhetorical device in action, instead of uses of the term. Hope you guys enjoy!