barnacleyoudaoicibaDictYouDict[barnacle 词源字典]
barnacle: [12] The term barnacle was originally applied to a type of goose, Branta leucopsis, which according to medieval legend grew on trees or on logs of wood. Various fanciful versions of its reproductive cycle existed, among them that it emerged from a fruit or that it grew attached to a tree by its beak, but the most tenacious was that it developed inside small shellfish attached to wood, rocks, etc by the seashore.

Hence by the end of the 16th century the term had come to be applied to these shellfish, and today that is its main sense. The word was originally bernak (it gained its -le ending in the 15th century) and came from medieval Latin bernaca, but its ultimate source is unknown.
[barnacle etymology, barnacle origin, 英语词源]
barnacle (n.)youdaoicibaDictYouDict
early 13c., "species of wild goose;" as a type of "shellfish," first recorded 1580s. Often derived from a Celtic source (compare Breton bernik, a kind of shellfish), but the application to the goose predates that of the shellfish in English. The goose nests in the Arctic in summer and returns to Europe in the winter, hence the mystery surrounding its reproduction. It was believed in ancient superstition to hatch from barnacle's shell, possibly because the crustacean's feathery stalks resemble goose down. The scientific name of the crustacean, Cirripedes, is from Greek cirri "curls of hair" + pedes "feet."