Any of various Cardium with a heart-shaped, radially ribbed "cockleshell." They have a tendency to be quite gritty and must be washed thoroughly to rid them of sand. Cockles, which have always been more popular in Europe than the United States, can be eaten raw or cooked, as with clams or oysters.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.