pectoral fin definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
either of a pair of fins, associated with the pectoral girdle, just behind the head of a fish, corresponding to the forelimbs of a higher vertebrate
pectoral fin definition by American Heritage Dictionary
Either of the anterior pair of fins attached to the pectoral girdle of fishes, corresponding to the forelimbs of higher vertebrates.