I. noun 1.
[Linguistics] each of two or more alternative forms of a letter of an alphabet or other grapheme, for example the capital, lower case, italic, and various handwritten forms of a letter.
[Phonetics] each of two or more letters or letter combinations representing a single phoneme in different words. Allographs of the phoneme /f/ include the (f) of ‘fake’ and the (ph) of ‘phase’.
II. derivatives allographic adjective
– origin 1950s: from allo- ‘other, different’ + grapheme.