brook
Synonym discussion
Sense: noun/1
For this sense, brook is a nature-focused word for a small flow of water in the countryside. Stream is the most general everyday choice and works in both ordinary speech and writing. Creek is especially common in North American English and often sounds more local or practical than brook. River refers to a larger body of flowing water, so it does not fit a narrow line of water behind a farm or through a wood. Choose brook when you want a gentle country picture: A narrow brook ran behind the farm. In everyday American speech, many people would more naturally say The kids fished in the creek after school.
Etymology
Modern English brook brings together two older words that ended up with the same spelling. The noun came from Old English broc, meaning a stream, and it was linked to older Germanic words connected with marshy ground. The verb came from Old English brucan, which first meant use or enjoy. That verb later developed the idea of being able to stomach something, and from there it reached the modern sense of tolerating or allowing it. So the water word and the formal verb look the same today, but they come from different historical roots.