barnacle UK /ˈbɑːnəkl̩/US /ˈbɑɹnəkl̩/noun 9verb 2forms 3 noun9 •A marine crustacean of the subclass Cirripedia that attaches itself to submerged surfaces such as tidal rocks or the bottoms of ships. •The barnacle goose. •(slang) A deprecated or obsolete file, image or other artifact that remains with a project even though it is no longer needed. •(slang) In electrical engineering, a change made to a product on the manufacturing floor that was not part of the original product design. •(slang) On printed circuit boards, a change such as soldering a wire in order to connect two points, or addition such as an added resistor or capacitor, subassembly or daughterboard. •(slang) A worldly sailor. •[in the plural] (slang, no longer used) A pair of spectacles. •[in the plural] (no longer used) An instrument like a pair of pincers, to fix on the nose of a vicious horse while shoeing so as to make it more tractable. •(slang, no longer used) A good job, or snack easily obtained. verb2 •To connect with or attach.Tokuda went over everything his grandfather had taught him, including the commentary that had barnacled on to the core knowledge. — 2009 •To press close against something.He turned a corner to where he supposed the cupboard might be, to find Howie and Alanna barnacled together in an embrace. — 2002 formsbarnacled · barnacling · barnacles