Protective outer bulb or envelope of the #0excludeGlossary Discharge (or HID) lamp.
Merriam-Webster Online Dictionary
jacket (noun)1.
a) a garment for the upper body usually having a front opening, collar, lapels, sleeves, and pockets
b) something worn or fastened around the body but not for use as clothing
2.
a) (1) the natural covering of an animal
(2) the fur or wool of a mammal
b) the skin of a potato
3.
an outer covering or casing as
a) (1) a thermally nonconducting cover
(2) a covering that encloses an intermediate space through which a temperature-controlling fluid circulates
(3) a tough cold-worked metal casing that forms the outer shell of a built-up bullet
b) (1) a wrapper or open envelope for a document
(2) an envelope for enclosing registered mail during delivery from one post office to another
c) (1) a detachable protective cover for a book
(2) a paper or cardboard envelope for a phonograph record
transitive verb
to put a jacket on enclose in or with a jacket
Merriam-Webster Online Thesaurus
jacket (noun)1.
something that encloses another thing especially to protect it
SYNONYMS:
armor, capsule, casing, cocoon, cover, covering, encasement, housing, hull, husk, jacket, pod, sheath, shellRELATED WORDS:
cartridge, cassette ( casette); bark, crust; carapace, house, mail, panoply, plate, plating, shield; cuticle, hide, skin; envelope, package, wrapper; backing, coating, coverture, facing2.
the hairy covering of a mammal especially when fine, soft, and thick
SYNONYMS:
coat, fleece, hair, jacket, pelage, pile, woolRELATED WORDS:
undercoat, underfur; hide, leather, pelt, skinJacket (Wikipedia)
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.
wrapper, cover, casing, shell, skin