A metonymy is a word or phrase that replaces the name of another word, which it is closely associated with. A metonymy adds flavor to a piece of writing by helping the writer sound less redundant. It addresses something in a more poetic and unique way. Authors can also add more complexity and meaning to ordinary words by using metonymy; furthermore, drawing the reader’s attention to what otherwise would not be noticed. This means bringing deeper meaning to simple objects or ideas.
Marcellus: Something is rotten in the state of Denmark.
(Hamlet by William Shakespeare)
Shakespeare used metonymy in his plays and poems. This line from Hamlet: “the state of Denmark” is repeated throughout the book. It is meant to stand in for the whole royal system and government.
"The pen is mightier than the sword."
(Richelieu by Edward Bulwer Lytton)