noun Download 🔗Share A fish of the order Pleuronectiformes, the adults of which have both eyes on one side and usually swim with the other side down, such as a flounder, a halibut, or a sole. Examples : "While walking on the beach, we saw several flatfishes camouflaged against the sandy bottom, their two eyes looking up from one side of their bodies. " fish animal biology nature Chat with AIVocabulary GamePractice Reading