The article describes the application OntoDictionary, which is designed to work with scientific mathematical articles and ontologies created in Protege. The application is able to create an ontology dictionary, split its elements into concepts, and process them in Boolean search. There is a functional for the selection of certain nominal groups from mathematical articles. The novelty lies in the creation and method of processing nominal groups containing formulas. Formulas are processed regardless of their type. The selection of candidates for terms has been constructed. Throughout the functional, a number of experiments have been performed with the ontology of mathematical knowledge of OntoMathPRO, which was also developed at the Kazan Federal University.