What does "trout" mean?

Trout: (Zoöl.) Any one of several species of marine fishes more or less resembling a trout in appearance or habits, but not belonging to the same family, especially the California rock trouts, the common squeteague, and the southern, or spotted, squeteague; -- called also salt-water trout, sea trout, shad trout, and gray trout. See Squeteague, and Rock trout under Rock. Trout perch (Zoöl.), a small fresh-water American fish (Percopsis guttatus), allied to the trout, but resembling a perch in its scales and mouth.