In linguistics, a superfamily (or macrofamily) is a phyletic unit encompassing several language families. The term is generally used for conjectural families, e.g. the Nostratic, Dené-Caucasian, Altaic, and Proto-World groupings. The term is typically invoked to describe theoretical associations between established language families (e.g. between Turkic, Mongolic, and Tungusic languages, and often – but not always – Korean and Japonic, in the case of Altaic), and has come to carry a connotation of hypothesis, and therefore, controversy.