There are analyzed the differential and integral signs of the notions “converse pair” and “word-formative pair” that make up the contents and methodological basis of the semantic and derivational approach in the conversion study. There is made the conclusion that the notion “word-formative pair” in relation to the notion “conversion pair” appears as the way to determine the derivational relations of the derivative conversions with the aim to demonstrate word-formative instruments in construction of the language semantic system.