barnacle

1. A marine crustacean of the subclass Cirripedia that attaches itself to submerged surfaces such as tidal rocks or the bottoms of ships.
2. The barnacle goose.
3. In electrical engineering, a change made to a product on the manufacturing floor that was not part of the original product design. (slang)
4. 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)
5. A deprecated or obsolete file, image or other artifact that remains with a project even though it is no longer needed. (slang)
6. A worldly sailor. (slang)

Plural barnacles