a short upper garment, extending downward to the hips; a short coat without skirts.-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.-in ordnance, a strengthening band surrounding and reenforcing the tube in which the charge is fired.-a garment resembling a waistcoat lined with cork, to serve as a life preserver; -- called also cork jacket.-to put a jacket on; to furnish, as a boiler, with a jacket.-to thrash; to beat.