order Percomorphi or·der·per·comorphi uncommon noun 1. one of the largest natural groups of fishes of both marine and fresh water: true perches; basses; tuna SynonymsPerciformesorder PerciformesPercomorphiorder Percomorphi Related words Broader terms animal order Parts Acanthopterygii Part of Percoideapercoid fishperchAnabantidaePercidaeTrichodontidaeOphidiidaeBrotulidae WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.