coatcoat1 /koʊt/ ●●● noun [countable] 1a piece of clothing that you wear over other clothes to keep you warm when you go outside: Put your coat on, it’s cold outside! He took off his coat and dropped it on the bed.2a jacket that you wear as part of a suit3a thin layer of something that covers a surface: a coat of paint4an animal’s fur: a dog with a black and brown coat5a light piece of clothing that a doctor, etc. wears over other clothes: a lab coat [Origin: 1300–1400 Old French cote]