Semantic_Type Semantic_Type Conceptual Entity A property that represents a description of the sort of thing or category to which a concept belongs in the context of the UMLS semantic network. Semantic Type Semantic_Type P106 In general, applying semantic types aids in allowing users (or computer programs) to draw conclusions about concepts by virtue of the categories to which they have been assigned. We use a set of semantic types developed for the UMLS Metathesaurus. There are currently 134 semantic types in the UMLS. The semantic type describes the sort of thing or category to which a concept belongs in the context of the UMLS semantic network.