acorn barnacle

/EY1 K AO0 R N B AA1 R N AH0 K AH0 L/
noun
  1. 1

    Any of several species of stalkless barnacles in the genus Balanus.

  2. 2

    Any barnacle in the order Sessilia.

Source: https://en.wiktionary.org/wiki/acorn%20barnacle