geoduck; gweduck [GOO-ee duhk] This huge, funny-looking SOFT-SHELL CLAM hails from the Pacific Northwest. It averages 3 pounds in weight and is distinguished by a long (up to 18-inch) neck (siphon) that extends from its 6-inch shell. The neck can be cut or ground and used in chowders. The body meat, when sliced, pounded and sautéed, resembles ABALONE. See also CLAMS; SHELLFISH.

from THE FOOD LOVER'S COMPANION, 2nd edition, by Sharon Tyler Herbst, Barron's Educational Services, Inc.