di-a-lect [dahy-uh-lekt] noun 1. Linguistics. a variety of a language that is distinguished from other varieties of the same language by features of phonology, grammar, and vocabulary, and by its use by a group of speakers who are set off from others geographically or socially. 2.a provincial, rural, or socially distinct variety of a language that differs from the standard language, especially when considered as substandard. 3. a special variety of a language: The literary dialect is usually taken as the standard language. 4. a language considered as one of a group that have a common ancestor: Persian, Latin, and English are Indo-European dialects. 5. jargon or cant.