Typology as a branch of linguistics comes from "type" or "typical", hence, it aims at establishing similar general linguistic categories serving as a basis for the classification of languages of different types, irrespective of their genealogical relationship.
Contrastive typology, as the notion itself reveals it, represents a linguistic subject of typology based on the method of comparison or contrasting. Like typology proper, which has hitherto been practised, contrastive typology also aims at establishing the most general structural types of languages on the basis of their dominant or common phonetical/phonetic, morphological, lexical and syntactic features.
Apart from this contrastive typology may equally treat dominant or common features only, as well as divergent features/phenomena only, which are found both in languages of the same structural type (synthetic, analytical, agglutinative, etc.) as well as in languages of different structural types (synthetic and analytical, agglutinative and incorporative, etc.)