Feature (linguistics) - in Phonology

In Phonology

In phonology, segments are categorized into natural classes on the basis of their distinctive features. Each feature describes a quality or characteristic of the natural class, such as voice or manner. A unique combination of features defines a phoneme.

Examples of phonemic or distinctive features are:, (binary features) and (a unary feature; also a place feature).

Surface representations can be expressed as the result of rules acting on the features of the underlying representation. These rules are formulated in terms of transformations on features.