Etymology Dictionary

BARNACLE (1),  a species of goose.  (Lat.?)   'A barnacle, bird, chelonalops;' Levins, 6. 2.   Ducange has 'Bernacæ, aves aucis palustribus similes,' with by-forms bernacelæ, berneschæ, bernestæ, and bernichæ.   Cotgrave has 'Bernaque, the fowle called a barnacle.'   β. The history of the word is very obscure; but see the account in Max Müller's Lectures on the Science of Language, 8th ed. ii. 602.   His theory is that the birds were Irish ones, i.e. aves Hibernicæ or Hiberniculæ; that the first syllable was dropped, as in Low Lat. bernagium for hybernagium, &c.; and that the word was assimilated to the name of a shell-fish.   See Barnacle (2).

BARNACLE (2),  a sort of small shell-fish.  (Lat.)   Spelt bernacles by Sir T. Browne, Vulg. Errors, bk. vi. c. 28. § 17.—Lat. bernacula, probably for pernacula, dimin. of perna; see this discussed in Max Müller, Lect. on the Science of Language, 8th ed. ii. 584.—Lat. perna, used by Pliny, Nat. Hist. 32. 55:  'Appellantur et pernæ concharum generis, circa Pontias insulas frequentissimæ.   Stant velut suillo crure longe in arena defixæ, hiantesque, qua limpitudo est, pedali non minus spatio, cibum venantur.'—Gk. πέρνα, lit. a ham.   ¶ Mr. Wedgwood compares Gael. bairneach, a limpet; Welsh brenig, a limpet; and proposes the Manx bayrn, a cap, 'as the etymon.'   R. Williams says, however, that Corn. brennic, limpets, is regularly formed from bron, the breast; from the shape. [†]

ADDENDA

BARNACLE (2).   We also find Irish bairneach, barneach, a limpet.   Possibly Celtic; see Ducange, who cites Giraldus Cambrensis, so that the word (in Celtic) is of some antiquity.