n.
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.
adj. also ce·ta·ceous (sĭ-tā'shəs)
Of, relating to, or belonging to the order Cetacea.
[From New Latin Cētācea, order name, from Latin cētus, whale. See Cetus.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
