Definition of "zebra mussel" []

• A small freshwater mussel (Dreissena polymorpha) with a usually striped shell, native to Eurasia but widely established since the late 1980s in the Great Lakes and other North American waterways. (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.