aphaeresis  (n.)

A term used in COMPARATIVE PHILOLOGY, and sometimes in modern PHONOLOGY, to refer to the DELETION of an INITIAL sound in a WORD; often contrasted with SYNCOPE and APOCOPE. Examples include the historical loss of /k/ in knife and such contractions as I’ve. Aphesis is a type of aphaeresis – the loss of an unstressed vowel at the beginning of a word (’gain).