Differences in cognitive perception of the concept ‘work activity’ in both languages influenced the onomastic mechanism of designation of work. The paper deals with the semantics of Russian lexical units ‘work’ (delo) within the concept ‘work activity’ in comparison with Czech. The selected lexeme is language-specific in Russian. The presented research focuses on one of the possibilities of signification ‘work activity’. The exact definition of the lexical meaning of the selected lexeme is problematic in Russian; therefore the proper use of the expression is for a non-native speaker very difficult. The amount of expressions, in which the lexical unit work (delo) acquires other meanings, is worth further exploration in terms of conceptualizing the work process within the Russian language picture of the world.