Interoperability through ontologies

In this paper we concentrate on facilitating and quickening mutual communications between several systems thus allowing their closely interconnection, alias interoperability. We discuss wide definition of word ontology and describe sets of criteria and properties that help us divide ontologies. For presentation of so far discovered ways of ontology utilization for our purposes we describe several model applications that help closer understanding and classifying of ontology applications. We split described applications into two categories: information purvey and mutual access to knowledge.