bullhead

Short definition from Wiktionary

Noun

1. 1
   any of a variety of related species of generally dark-colored catfish in the family Ictaluridae: The black bullhead, Ameiurus melas.
2. 2
   any of a variety of related species of generally dark-colored catfish in the family Ictaluridae: The brown bullhead, Ameiurus nebulosus.
3. 3
   any of a variety of related species of generally dark-colored catfish in the family Ictaluridae: The yellow bullhead, Ameiurus natalis.
4. 4
   Any of various sculpins of the suborder Scorpaenoidei
5. 5
   The European bullhead, Cottus gobio.
6. 6
   A fish of species Gobiomorphus gobioides.
7. 7
   A bullhead shark (Heterodontus spp.).
8. 8
   An obstinate person.
9. 9
   A bullhead rail.
10. 10
    A chronograph (watch or stopwatch) with two push buttons arranged like the horns of a bull on the top end of the case, typically with the crown between them.