different between izzard vs gizzard

English

Middle English izod, ezod, ezed, from Old French et zede (literally “and zed”), as spoken when reciting the alphabet.

izzard (plural izzards)

(Scotland, and archaically in England and Ireland) The letter Z; zed, zee.
- 1773, Oliver Goldsmith, She Stoops to Conquer
  ... [Reading.] Dear Sir,—ay, that's that. Then there's an M, and a T, and an S, but whether the next be an izzard, or an R, confound me, I cannot tell.

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

gizzard (plural gizzards)

A specialized organ constructed of thick muscular walls found in the digestive tract of some animals, including archosaurs, birds, earthworms, some gastropods, some fish, and some crustaceans used for grinding up food, often aided by particles of stone or grit.

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