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.
a. a form of a language spoken in a particular geographical area or by members of a particular social class or occupational group, distinguished by its vocabulary, grammar, and pronunciation
b. a form of a language that is considered inferior: the farmer spoke dialect and was despised by the merchants
c. (as modifier): a dialect word
[C16: from Latin dialectus, from Greek dialektos speech, dialect, discourse, from dialegesthai to converse, from legein to talk, speak]
1577, from M.Fr. dialecte, from L. dialectus "local language, way of speaking, conversation," from Gk. dialektos, from dialegesthai "converse with each other," from dia- "across, between" + legein "speak" (see lecture).