gizzard

Etymology

From Middle English gyser, geser, from Old French gesier, giser et al. (French gésier), from Latin gigēria.

noun

1. A specialized organ constructed of thick muscular walls found in the digestive tract of some animals, including archosaurs (including crocodilians and birds), earthworms, some gastropods, some fish, and some crustaceans, and used for grinding up food, often aided by particles of stone or grit.
   As fortune has it, kingbirds, like owls, lack a grinding gizzard and regurgitate hard fragments from their meals. 2016, Justin O. Schmidt, The Sting of the Wild, Johns Hopkins University Press,, page 29
2. (slang) The (human) stomach.
   "Pushing a man's face into his own breakfast is beyond rules or reason, and deserves a punch in the gizzard." 1918, Norman Lindsay, The Magic Pudding, Sydney: Angus and Robertson, page 51