Source : Webster's Revised Unabridged Dictionary (1913)

Barnacle \Bar"na*cle\, n. [Prob. from E. barnacle a kind of
   goose, which was popularly supposed to grow from this
   shellfish; but perh. from LL. bernacula for pernacula, dim.
   of perna ham, sea mussel; cf. Gr. ? ham Cf. F. bernacle,
   barnacle, E. barnacle a goose; and Ir. bairneach, barneach,
   limpet.] (Zo["o]l.)
   Any cirriped crustacean adhering to rocks, floating timber,
   ships, etc., esp.
   (a) the sessile species (genus {Balanus} and allies), and
   (b) the stalked or goose barnacles (genus {Lepas} and
       allies). See {Cirripedia}, and {Goose barnacle}.

   {Barnacle eater} (Zo["o]l.), the orange filefish.

   {Barnacle scale} (Zo["o]l.), a bark louse ({Ceroplastes
      cirripediformis}) of the orange and quince trees in
      Florida. The female scale curiously resembles a sessile
      barnacle in form.