bar ‧ na ‧ cle /ˈbɑːnək ə l $ ˈbɑːr-/ BrE AmE noun [countable]
[ Date: 1500-1600 ; Origin: barnacle type of goose (12-21 centuries) , from Medieval Latin bernaca ; from the former belief that the goose was born from a barnacle ]
a small sea animal with a hard shell that sticks firmly to rocks and the bottom of boats