noun a thick muscular stomach found in many invertebrate animals.
2. gizzard ·noun a stomach armed with chitinous or shelly plates or teeth, as in certain insects and mollusks.
3. gizzard ·noun the second, or true, muscular stomach of birds, in which the food is crushed and ground, after being softened in the glandular stomach (crop), or lower part of the esophagus; the gigerium.