- any of several small sharks, especially of the genera Mustelus and Squalus, that are destructive to food fishes.
- any of various other fishes, such as the bowfin.
- any of several small spotted European sharks, esp Scyliorhinus caniculus (lesser spotted dogfish): family Scyliorhinidae
- any small shark of the family Squalidae, esp Squalus acanthias (spiny dogfish), typically having a spine on each dorsal fin
- any small smooth-skinned shark of the family Triakidae, esp Mustelus canis (smooth dogfish or smooth hound)
- a less common name for the bowfin
