Description: The method of calculation of semantic equivalence of two naturally-linguistic forms, presented as semantic functions is offered in the article. Sense of linguistic forms is limited to the level of lexical semantics, i.e. by the base of knowledges, presented as an explanatory dictionary, where every value of word is described a semantic function. In basis of method presentation of semantic function lies the oriented tree, where every top is noted a semantic function. A method consists of tree traversal and establishment for every pair of tops of equivalence in the plan of lexical semantics. The operation of calculation of equivalence can be used for the automatic analysis of naturally-linguistic texts, at a context information retrieval.
Keywords: human language, explanatory dictionary, semantic function, semantic dictionary, equivalence of functions, formalization of human language