"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", 1930s: from allo- 'other, different' + phoneme.[allophone etymology, allophone origin, 英语词源]