Some figures of speech (for example, anaphora or anthropomorphism) are very popular. Every poet uses them.

Synecdoche isn't a widespread literary device.

What is Synecdoche?

Let's begin with an example from everyday life:

She decided to buy a new set of wheels.

What about this sentence? A woman is going to buy a car.

In synecdoche a part of something represents the whole. It is also possible, that a whole represents a part:

Italy has won four World Cups - in 1934, 1938, 1982, 2006.

We said “Italy” instead of “Italy's national soccer team”.

Examples in English Literature

The Eyes around - had wrung them dry -

And Breaths were gathering...

I heard a Fly buzz when I died by Emily Dickinson

Tell that its sculptor well those passions read

Which yet survive, stamped on these lifeless things,

The hand that mocked them, and the heart that fed;

And on the pedestal, these words appear:

My name is Ozymandias, King of Kings;

Look on my Works, ye Mighty, and despair!

Ozymandias by Percy Bysshe Shelley

And let us mind, faint heart ne'er wan

                                 A lady fair:

Wha does the utmost that he can,

Will whiles do mair.

To Dr. Blacklock by Robert Burns

The figure forms a picture, helps readers to understand the author's thoughts, as you see.

Metonymy and Synecdoche 

Synecdoche are often called metonymy by mistake. They both use a word or a phrase to represent something else.

Nevertheless in metonymy the phrase or the word we use to describe another thing doesn't always denote a part of that thing.

Speaking about a businessman, we can call the person “suit”. It is a case of metonymy. Two objects are closely linked, but suits aren't necessarily businessmen's part.