Definition of "cetacean" [ce•ta•cean]

• Any of various aquatic, chiefly marine mammals of the order Cetacea, including the whales, dolphins, and porpoises, characterized by a nearly hairless body, anterior limbs modified into broad flippers, vestigial posterior limbs, and a flat notched tail. (noun)
• Of, relating to, or belonging to the order Cetacea. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Mark wasn't sure if he meant he was composing it for them to hear or that he was composing the music on their behalf, like some kind of cetacean dictation machine."
• "I think that Tilly's behavior on balance does indicate a kind of cetacean psychosis."
• "Description: The recent likely extinction of the baiji or Chinese river dolphin, makes the vaquita (Phocoena sinus)? the Gulf of California porpoise? the most endangered cetacean."