The Collaborative International Dictionary of English v.0.48:
Trout \Trout\ (trout), n. [AS. truht, L. tructa, tructus; akin
to Gr. trw`kths a sea fish with sharp teeth, fr. trw`gein to
1. (Zool.) Any one of numerous species of fishes belonging to
Salmo, Salvelinus, and allied genera of the family
Salmonidae. They are highly esteemed as game fishes and
for the quality of their flesh. All the species breed in
fresh water, but after spawning many of them descend to
the sea if they have an opportunity.
Note: The most important European species are the river, or
brown, trout (Salmo fario), the salmon trout, and the
sewen. The most important American species are the
brook, speckled, or red-spotted, trout (Salvelinus
fontinalis) of the Northern United States and Canada;
the red-spotted trout, or Dolly Varden (see Malma);
the lake trout (see Namaycush); the black-spotted,
mountain, or silver, trout (Salmo purpuratus); the
golden, or rainbow, trout (see under Rainbow); the
blueback trout (see Oquassa); and the salmon trout
(see under Salmon.) The European trout has been
introduced into America.
2. (Zool.) 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 (Zool.), a small fresh-water American fish
(Percopsis guttatus), allied to the trout, but
resembling a perch in its scales and mouth.