Protective outer bulb or envelope of the #0excludeGlossary Discharge (or HID) lamp.
A jacket is a garment for the upper body, usually extending below the hips. A jacket typically has sleeves and fastens in the front or slightly on the side. Jackets without sleeves are vests. A jacket is generally lighter, tighter-fitting, and less insulating than a coat, but both are outerwear. Some jackets are fashionable, while some others serve as protective clothing.

English
Etymology
From Middle French jacquet, diminutive of Old French jaque.
Pronunciation
- (Received Pronunciation) IPA(key): /ˈd͡ʒæk.ɪt/
- (US)
- (General American) IPA(key): /ˈd͡ʒæk.ɪt/
-
- (weak vowel merger) IPA(key): /ˈd͡ʒæk.ət/
- Hyphenation: jack‧et
- Rhymes: -ækɪt
Noun
jacket (plural jackets)
- A piece of clothing worn on the upper body outside a shirt or blouse, often waist length to thigh length.