noun

• (linguistics, strict sense) A lect (often a regional or minority language) as part of a group or family of languages, especially if they are viewed as a single language, or if contrasted with a standardized idiom that is considered the 'true' form of the language (for example, Cantonese as contrasted with Mandarin Chinese or Bavarian as contrasted with Standard German).
• (linguistics, broad sense) A variety of a language that is characteristic of a particular area, community, or social group, differing from other varieties of the same language in relatively minor ways as regards grammar, phonology, and lexicon.
• (derogatory) Language that is perceived as substandard or wrong.
• (colloquial, offensive) A language existing only in an oral or non-standardized form, especially a language spoken in a developing country or an isolated region.
• (computing, programming) A variant of a non-standardized programming language.
• (ornithology) A variant form of the vocalizations of a bird species restricted to a certain area or population.