Shucks fresh or steamed shellfish, such as oysters, clams, or scallops (bivalves), preparatory to canning, freezing, or fresh packing: Holds shellfish firmly or against block and forces shucking knife between halves of shell at hinge juncture. Twists knife to sever muscles holding shell closed and pries open. Cuts shellfish from shell, flips it into container, and discards shell. May break off edges of shells before shucking, using hatchet. May be designated according to shellfish shucked as Clam Shucker (can. & preserv.); Oyster Shucker (can. & preserv.); Scallop Shucker (can. & preserv.).