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”.
The kettle is boiling. (water in the kettle)
He took to the bottle.他爱上了喝酒。 (wine in the bottle)
I’m reading Lu Xun. ( Lu Xun’s works)
He’s listening to Beethoven. (Beethoven’s works)
He is booked out for the whole season.他这个季演出的票全订出去了 。
(the tickets for his concerts)
When she entered high school, she would wear a wardrobe that no one else would be able to match.当她上中学时？她所穿的衣服任何一个人都没法比。
They will resort to the sword if the negotiation does no work.
She is the first violin in the band.她是乐队中的第一小提琴手。
A figure of speech in which a part is used for the whole, the whole for a part, the specific for the general, the general for the specific, or the material for the thing from which it is made.
Young people should have more respect for gray hairs.
He saw some new faces in the classroom.
A fleet of ten sails \ To earn one’s bread \ To count heads
Many hands provide great strength.
The poor man had twelve mouths to feed.
Lend me your ears. ( give me your attention.)
Both are figures of speech used in rhetoric. They’re not the same thing, though metonymy is often interpreted so widely that synecdoche can be regarded as a special case of it.
As for Synecdoche, You use this when you speak of a part of something but mean the whole thing. When Patrick O’Brian has Captain Jack Aubrey tell his first lieutenant；陆军中尉？ to “let the hands go to dinner” he’s employing synecdoche, because he’s using a part (the hand) for the whole man. You can also reverse the whole and
the part, so using a word for something when you only mean part of it. This often comes up in sport: a commentator might say that “The West Indies has lost to England” when he means that the West Indian team has lost to the English one. America is often used as synecdoche in this second sense, as the word refers to the whole continent but is frequently applied to a part of it, the USA.
Metonymy is similar, but uses something more generally or loosely associated with a concept to stand in for it. When Americans speak of the Oval Office；美国总统办公
室？, for example, they are really referring to the activity within it, the position or function of the President. It’s a linked term, and so a metonym. British writers refer similarly to the Crown；王冠？, when they’re really discussing the powers, authority
and responsibilities of the monarchy；君主政体？, which is symbolized by the crown.
The difference between synecdoche and metonymy is that in metonymy the word you employ is linked to the concept you are really talking about, but isn’t actually a part of
it. Another example is the turf；草皮？ for horse racing. But the distinction isn’t
always obvious and often can’t be rigorously applied, and many people use metonymy to mean both.