ech·i·na·ce·a (?k??-n??s?-?, -n??sh?)n.1. Any of several coneflowers of the genus Echinacea, having usually pinkish-purple ray flowers.2. The roots, seeds, or other parts of such a plant, used in herbal medicine.[New Latin Ech?n?cea, genus name, from Latin ech?nus, sea urchin (from its rough leaves); see echinus.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.echinacea (??k??ne????) n1. (Plants) Also called: purple coneflower either of the two N American plants of the genus Echinacea, having flower heads with purple rays and black centres: family Compositae (composites). See coneflower2. (Plants) the powdered root of either of these plants, used to stimulate the immune system[from New Latin, from Latin ech?n?tus prickly, from ech?nus hedgehog]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014