Definify.com

Webster 1913 Edition

‖

Noun.

[Gr. [GREEK] a letting go; [GREEK] + [GREEK] to let go.]

The loss of a short unaccented vowel at the beginning of a word; – the result of a phonetic process;

as,

squire

for

esquire

New Eng. Dict.

aphesis ‎(plural apheses)

(linguistics, prosody) The loss of the initial unstressed vowel of a word.
The word "scarp" is derived from "escarp" by aphesis.

loss of the initial unstressed vowel of a word