Onomatopoeia is a figure of speech in which the sound reflects the sense. In simple words, it is the formation and use of words to imitate sounds.
The word “onomatopoeia” comes from the combination of two Greek words, onoma meaning “name” and poiein meaning “to make,” so onomatopoeia literally means “to make a name (or sound).”
For example, Rustle is the sound of something dry, like paper, brushing together, but it can also indicate the action of someone moving papers around and causing them to brush together, thus making this noise. There are so many examples like meow, which refers to the sound of a cat. Also we can refer to chirp, click, dong, crackle, moo, pop, whizz, whoosh, zoom as onomatopoeia. It is very common in verse and fairly common in prose and is found in many pieces of literature at all times.
As a rule, it is deliberately used to achieve a special effect, as in these lines from T.S.Eliot’s Dry Salvages:
When the train starts, and the passengers are settled
To fruit, periodicals and business letters
(And those who saw them off have left the platform)
Their faces relax from grief into relief,
To the sleepy rhythm of a hundred hours.
The whole passage is subtly onomatopoeic, the rhythm of the second line is a beautifully skilful evocation of the clickety-click of wheels on rails.