izzard
The letter Z; zed, zee.
... [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.
Where it comes from
From Middle English izod, ezod, ezed, probably from Middle French et zede (literally “and zed”), as spoken when reciting the alphabet.
Adapted from the Wiktionary entry izzard (CC BY-SA 4.0).