etacism

Century Dictionary and Cyclopedia

1. n. The Erasmian pronunciation of ancient Greek, characterized by giving the letter η its ancient sound of a in mate or ey in they: opposed to iotacism, the Reuchlinian and modern Greek method, which gives to η and to some other vowels and some diphthongs the sound of e in be or i in machine.

Wiktionary

1. n. grammar The pronunciation of the Greek eta like the Italian long e, or the vowel in the English word ate.

GNU Webster's 1913

1. n. (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.