Ling.
1. a feature of the sound system of a language that serves as the crucial distinguishing mark between two phonemes, as the distinctive feature of voicing, which distinguishes b from p in English, or nasality, which distinguishes m from b and p.
2. any of a set of phonetic properties, as coronal, nasal, or strident, serving as a basic unit of phonological analysis by which the sounds that are significant in a language can be characterized and distinguished from one another.
3. a component or phonetic feature characterizing a phoneme.
[ 1925-30 ]