allophone

One of the realisations of a phoneme. Phonemes are realised differently in different positions. Depending on the other sounds occurring in the phonetic context, these different realisations of a phoneme are called the allophones of the phoneme. A highly frequent example is the realization of the plural in English {Z1} which is either realized as a voiced or voiceless allophone depending on the quality of the previous phoneme. The morpho-phonemic rule representing the distribution of the plural s realisations looks like this: