APA Dictionary of Psychology

n. in linguistics, a speech sound that plays a meaningful role in a language and cannot be analyzed into smaller meaningful sounds, conventionally indicated by slash symbols: /b/. A speech sound is held to be meaningful in a given language if its contrast with other sounds is used to mark distinctions of meaning. In English, for example, /p/ and /b/ are phonemes because they distinguish between [pan] and [ban] and other such pairs (see minimal pair). —phonemic adj.