jack ‧ et S2 W3 /ˈdʒækət, ˈdʒækɪt/ BrE AmE noun [countable]
[ Date: 1400-1500 ; Language: French ; Origin: jaquet , from jaque 'short coat' , probably from jacque 'poor farmer' , from the male name Jacques 'James' ]
1 . a short light coat
a leather/denim/linen etc jacket
a suede jacket
⇨ ↑ bomber jacket , ↑ dinner jacket , ↑ life jacket , ↑ straitjacket (1)
2 . the part of a suit that covers the top part of your body:
Gene has to wear a jacket and tie to work.
tweed jackets
⇨ ↑ sports jacket
3 . a stiff piece of folded paper that fits over the cover of a book to protect it SYN dust jacket
4 . American English a stiff paper cover that protects a record SYN sleeve British English
5 . a cover that surrounds and protects some types of machines