Webster’s Revised Unabridged Dictionary · 1913 Etacism E′ta·cism (ā′tȧ·sĭz'm), n. [Gr. ἦτα the letter η, ē. Cf. Itacism.] (Greek Gram.) The pronunciation of the Greek η (eta) like the Italian e long, that is like a in the English word ate. See Itacism. ‹ Etaac Etacist ›