Definition of "sand dollar" []

• Any of various thin circular echinoderms of the class Echinoidea, especially Echinarachnius parma, of coastal northern Atlantic and Pacific waters, having a covering of short movable spines. (noun)
• The disklike internal skeleton of a sand dollar, having five radially symmetric oblong markings and often a pattern of slotlike holes. (noun)

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.

• "For his part, Eli attempted the defense that every afflicted and hunted beast attempts, the defense of a sand dollar that settles into the ocean floor or a beaten dog that cowers beneath his forepaws, the worthless twin defenses of shrinkage and anonymity."