Activity theory (AT) is the most known spin-off of Russian psychology. It disseminated in international science through the works of A.N. Leontiev, first of all, through his “Activity, Consciousness and Personality” book. Despite the interest AT caused in the international scientific community, foreign colleagues were faced from the very beginning with substantial difficulties in their quest to comprehend the AT theoretical approach. The main predicament was the conceptual apparatus, the language of the AT, which was very different from the one used in international science. It was clear that the scientific potential of Activity Theory will not be realized by Englishspeaking users if sufficient attention would not be given to clarifying meanings of the fundamental terms of AT, and appropriate attempts were immediately taken. An important example of efforts to comprehend the AT vocabulary, was Tolman's “The basic vocabulary of Activity Theory” (1988), which provided quotations for vari64 ous terms used in Acti