n. A species of wild goose, Anser bernicla or Bernicla leucopsis, also called barnacle-goose or bernacle-goose.n. A species of stalked cirriped, Lepas anatifera, of the family Lepadidæ, found hanging in clusters by the long peduncle to the bottoms of ships, to floating timber, or to submerged wood of any kind; the goose-mussel, fabled to fall from its support and turn into a goose (see def. 1).n. Anything resembling a barnacle (in sense 2).n. A person holding on tenaciously to a place or position; one who is a useless or incompetent fixture in an office or employment; a follower who will not be dismissed or shaken off.n. [Cf. barnard.] A decoy swindler.To fix or attach, as a barnacle upon the bottom of a ship.n. A kind of bit or muzzle used to restrain an unruly horse or ass; now (usually in the plural), an instrument consisting of two branches joined at one end with a hinge, placed on a horse's nose to restrain him while being shod, bled, or dressed.n. Hence An instrument of torture applied in a similar way to persons.n. plural Spectacles.To apply barnacles to: as, to barnacle a horse.