jacketEnglishOxford American Thesaurusjacket noun 1 coat, jerkin, tunic, blazer, blouson, bomber jacket, Harrington, parka, anorak, puffa, windbreaker; sports jacket, dinner jacket, tuxedo; British donkey jacket, waterproof, cagoule, windcheater. 2 a jacket for your hot-water tank will save at least $15 a year: wrapping, wrapper, wrap, sleeve, sheath, sheathing, envelope, cover, covering; casing, case, shell, housing, encasement, capsule; technical integument.