choo
interj. A1 Beginner US //ˈtʃu// choo
interj. the sound people make to imitate a steam train. You might say this when playing with children or talking about old engines.
interj. an onomatopoeic representation of the sound produced by a steam locomotive. Frequently doubled as 'choo-choo' in child-directed speech.
The little boy pointed at the train and said choo.
The children lined up behind their teacher and made a loud 'choo' sound as they pretended to be a train.
While modern electric trains hum quietly, the classic steam engine is still immortalized in children's literature by the rhythmic 'choo' of its exhaust.
Usage
Often used as a reduplicated form ('choo-choo') which can function as a nursery noun for a train.