In phonetics and phonology, apheresis (; British English: aphaeresis) is the loss of one or more sounds from the beginning of a word, especially the loss of an unstressed vowel, thus producing a new form called an aphetism .
Apheresis comes from Greek aphairesis, "taking away" from ? aphaireo from apo, "away" and haireo, "to take". Aphetism comes from Greek aphesis, "letting go" from aphiemi from apo, "away" and ? híemi, "send forth".
In historical phonetics and phonology, the term "apheresis" is often limited to the loss of an unstressed vowel. The Oxford English Dictionary gives that particular kind of apheresis the name aphesis (; from Greek ).
Synchronic apheresis is more likely to occur in informal speech than in careful speech: 'scuse me vs. excuse me, How 'bout that? and How about that? It typically supplies the input enabling acceptance of apheresized forms historically, such as especially > specially. The result may be doublets, such as especially and specially, or the pre-apheresis form may fail to survive (Old French eschars > English scarce). An intermediate status is common in which both forms continue to exist but lose their transparent semantic relationship: abate 'decrease, moderate', with bate now confined to the locution with bated breath 'with breath held back'.