Aphesis

In phonetics and phonology, apheresis is a sound change in which a word-initial vowel is lost, e.g., American →'Merican. In a broader sense, it can refer to the loss of any initial sound from a word or, in a less technical sense, to the loss of one or more sounds from the beginning of a word. The more specific term aphesis is sometimes used to refer to the loss of unstressed vowels.