rainbow trout rain·bowt·rout uncommon noun 1. flesh of pacific trout that migrate from salt to fresh water Synonymsrainbow trout 2. found in Pacific coastal waters and streams from lower California to Alaska Synonymsrainbow troutSalmo gairdneri Related words Broader terms trout Parts rainbow troutSalmo Part of rainbow trout WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.