Definition of bullheads:
(n) :
(Canada, US) any of a variety of related species of generally dark-colored catfish in the family Ictaluridae.
(n) :
(Canada, US) The black bullhead, Ameiurus melas.
(n) :
(Canada, US) The brown bullhead, Ameiurus nebulosus.
(n) :
(Canada, US) The yellow bullhead, Ameiurus natalis.
(n) :
(Europe, Asia) Any of various sculpins of the suborder Scorpaenoidei
(n) :
(Europe, Asia) The European bullhead, Cottus gobio.