What is a synecdoche?
It is a figure of speech in which, most often, a part of something is used to refer to its whole.
Let's have a look at some of these
"The captain commands one hundred sails" Obviously the Captain doesn't actually command one hundred sails, but the sails are part of a ship, so it is a way of saying that the captain commands one hundred ships, the ships being the thing of which a sail is a part of.
Using synecdoche's is a way of making what you are saying more interesting.
If you said "check out my new wheels," "wheels" is another example of synecdoche, used here to refer to a "car." A part of a car, in this example, represents the whole of the car. So we are saying check out my new car. Synecdoche's are often used in speech my people to draw attention to an object. Mostly people use a synecdoche to spice up everyday language.
We can use this example of a car perhaps in a different way As we saw, "wheels" was a synecdoche for "car." Another common word for car is a "ride." so we could say, "Let's take my new ride out for a spin." The car is replaced by the word ride. You ride in a car, so it's a related word, but it's not an element of a car. This looks like a synecdoche but it isn't. Instead this is a metonymy. Whilst a synecdoche takes an element of a word or phrase and uses it to refer to the whole, a metonymy replaces the word or phrase entirely with a related concept. Some synecdoche's are a form of metonymy.
Here are some examples
The phrase "hired hands" can be used to refer to workers. We have many hired hands here.
The word "head" can refer to counting cattle or people. I own thirty head of cattle.
The word "bread" can be used to represent food in general or possibly money. He is the breadwinner;. Making films is my bread and butter.
The word hand refers to someone. Can you lend me a hand?
The word threads refers to clothing. Do you like my new threads?
The word "boots" refers to soldiers. We managed to get boots on the ground in Kuwait.
The phrase ABC's is apart of the alphabet which is part of language. Have you learnt your ABC's
The word "bubbly" refers to champagne. Would you care for a glass of bubbly?
The word plastic can be used to talk about a credit card. I will put this on my plastic.
The word eyes refer to contact lenses. Let me put my eyes in, then I can see you.
If you think that you haven’t heard of any synecdoche's then there are many using in common English. Here are a few well-known synecdoche's.
All hands on deck
Faces in the crowd
Lend me your ears
Keep the change
Have a nice day
You have my heart
Hit the sheets
Much of the works of Shakespeare uses synecdoche's and many of these have appeared in common usage.
Friends, Romans, Countrymen, lend me your ears." Julius Caesar, Shakespeare