In phonetics, aphaeresis (pronounced /əˈfɪərɨsɪs/, from Greekapo away, hairein to take), also known as aphesis (pronounced /ˈæfɨsɪs/, from Greekapo away, hienai to send), is the loss of one or more sounds from the beginning of a word; especially, the loss of an unstressed vowel.
Aphaeresis or aphesis as a historical sound change
In historical phonetics, the term "aphaeresis" is often but not always limited to the loss of an unstressed vowel. (The Oxford English Dictionary gives this particular kind of aphaeresis the name aphesis/ˈæfɨsɪs/.)
The loss of any sound
English [k]nife pronounced /ˈnaɪf/
Swedish [st]rand > Finnish ranta "beach"
The loss of an unstressed vowel
Greek episkopos > Vulgar Latin[e]biscopu > English bishop
English [a]cute > cute
English [E]gyptian > Gyptian > Gypsy
English [a]mend > mend
English [e]scape + goat > scapegoat
Old French evaniss- > English vanish
English esquire > squire
Aphaeresis as a poetic device
English it is > poetic 'tis
Aphaeresis in informal speech
Spanish está > Rioplatense Spanish [e]tá > ta ("is")