The paper defines three logical criteria for semantic adequacy of an applied ontology. All criteria are based on the idea to the effect that when an ontology construed as a formal theory allows for swapping some items in its vocabulary, then it does not sufficiently differentiate between the meanings of these items and, consequently, the semantic aspect of this vocabulary cannot be claimed to be sufficiently characterised. Besides providing the formal definitions of those criteria and proving some simple correlations therebetween I present the empirical results of their implementation.