\Jack"et\, n. [F. jaquette, dim. of jaque. See 3d {Jack},
n.]
1. A short upper garment, extending downward to the hips; a
   short coat without skirts.
2. An outer covering for anything, esp. a covering of some
   nonconducting material such as wood or felt, used to
   prevent radiation of heat, as from a steam boiler,
   cylinder, pipe, etc.
3. (Mil.) In ordnance, a strengthening band surrounding and
   re["e]nforcing the tube in which the charge is fired.
4. A garment resembling a waistcoat lined with cork, to serve
   as a life preserver; -- called also {cork jacket}.
{Blue jacket}. (Naut.) See under {Blue}.
{Steam jacket}, a space filled with steam between an inner
   and an outer cylinder, or between a casing and a
   receptacle, as a kettle.
{To dust one's jacket}, to give one a beating. [Colloq.]

\Jack"et\, v. t.
1. To put a jacket on; to furnish, as a boiler, with a
   jacket.
2. To thrash; to beat. [Low]