Aphesis, Apheresis, Aphaeresis (from Greek apo- away, and hairein to take) is the removal of an initial, usually unstressed vowel or a syllable of a word. As such, it is a form of metaplasm and elision.
Similar concepts are apocopation, the removal of the end of a word, and syncope, the removal of the middle of a word.
The opposite of aphesis (adding an epenthetic initial sound) is called prothesis.
Aphaeresis is an important concept in etymology as it is the means by which a number of words have arrived at their modern form. For example, the English word bishop comes from the Greek επισκοπος (episkopos) via the Latin ebiscopus .
Examples in English:
In English poetry, it often becomes 't by aphesis: 'Tis so from It is so, etc.
In Rioplatense Spanish, where syllable-final s is often reduced to /h/ and then deleted, aphesis produces colloquial contracted forms of the copular verb estar:
In Japanese, the initial i of the stative verb iru is elided in rapid speech when forming a compound verb: