[Phonetics] any of the various phonetic realizations of a phoneme in a language, which do not contribute to distinctions of meaning. For example, in English an aspirated p (as in pin) and unaspirated p (as in spin) are allophones of /p/, whereas in ancient Greek the distinction was phonemic.
II. derivatives allophonic adjective
– origin 1930s: from allo- ‘other, different’ + phoneme.