ess-

Etymology
From, from.

Prefix

 * 1) ex-, out
 * : non-, dis-
 * : non-, dis-
 * : non-, dis-
 * : non-, dis-

Usage notes
Originally, ess- manifested in the following distribution in stressed syllables:
 * ess- proper before vowels and s-
 * before resonants
 * before stops, blocking lenition

Already in Old Irish, however, ess- proper can be seen encroaching on the environments of its other allomorphs.