From Longman Dictionary of Contemporary Englishtrouttrout /traʊt/ ●○○ noun 1 
(plural trout) [countable, uncountable]HBF a common river-fish, often used for food, or the flesh of this fish2 → old trout
(plural trout) [countable, uncountable]HBF a common river-fish, often used for food, or the flesh of this fish2 → old troutExamples from the Corpus
trout• The Arundell Arms Hotel in Devon runs a variety of courses in wet and dry fly fishing for salmon and trout.• Providing fresh trout for dinner was rarely a problem.• Winnisquam has some good lake trout, so the guys say, but this part of Winnipesaukee is prime.• Insects falling into the water during the summer provide a substantial proportion of the diet of trout.• That includes eight lakes that will receive bonus trophy-size trout in the 5-to 12-pound class.• The loch is full of wild brown trout; where a basket of thirty trout is the rule, rather than the exception.Origin trout (1000-1100) Late Latin tructa type of fish with sharp teeth, from Greek, from trogein “to bite” 