Source : Webster's Revised Unabridged Dictionary (1913)

Itacism \I"ta*cism\, n. [Cf. F. itacisme. See {Etacism}, and cf.
   {Iotacism}.] (Greek Gram.)
   Pronunciation of ? (eta) as the modern Greeks pronounce it,
   that is, like e in the English word be. This was the
   pronunciation advocated by Reu?hlin and his followers, in
   opposition to the etacism of Erasmus. See {Etacism}.

         In all such questions between ? and a? the confusing
         element of itacism comes in.             --Alford.