1 a piece of clothing worn on the top half of the body over a shirt, etc. that has sleeves and fastens down the front; a short, light coat:
a denim / tweed jacket * I have to wear a jacket and tie to work.
seealsoBOMBERJACKET, DINNERJACKET, DONKEYJACKET, FLAKJACKET, LIFEJACKET, SMOKINGJACKET, SPORTSJACKET, STRAITJACKET
2 (also dust jacket) a loose paper cover for a book, usually with a design or picture on it
3 an outer cover around a hot water pipe, etc., for example to reduce loss of heat
4 (BrE) the skin of a baked potato:
jacket potatoes (= baked potatoes) * potatoes baked in their jackets
5 (especially AmE) = SLEEVE(3)
