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n. 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. (Mil.) In ordnance, a strengthening band surrounding and reinforcing 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.

 - Blue jacket. (Naut.) See under Blue.

 - Steam jacket, a space filled with steam between an ...