- A marine crustacean of the subclass Cirripedia that attaches itself to submerged surfaces such as tidal rocks or the bottoms of ships.
- (computing, 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, obsolete) A good job, or snack easily obtained.
- (engineering, slang) In electrical engineering, a change made to a product on the manufacturing floor that was not part of the original product design.
- (archaic, Britain) A nickname for spectacles.
- The barnacle goose.
- (obsolete) 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.
- To press close against something.
- To connect with or attach.