Source : Webster's Revised Unabridged Dictionary (1913)

Izzard \Iz"zard\, n. (Zo["o]l.)
   See {Izard}.

Izzard \Iz"zard\, n. [Formerly ezed, prob. fr. F. et z['E]de and
   z.]
   The letter z; -- formerly so called.

Source : WordNet®

izzard
     n : the 26th letter of the Roman alphabet; "the British call Z
         zed and the Scots call it ezed but Americans call it
         zee"; "he doesn't know A from izzard" [syn: {Z}, {zee}, {zed},
          {ezed}]