My presentation is about the classification problems arising during the elaboration of the study entitled Információkereső tezaurusz a magyar leíró nyelvészet témaköréből (?Information Retrieval Thesaurus for Hungarian Descriptive Linguistics?), written as a dissertation at the Faculty of Information Sciences of Debrecen University in 2006, and its considerably revised version edited with Relex thesaurus management software [9], and the options of solution.

1. Briefly about terminological problems: shortcomings of terminology and the possibilities of filling the 'empty linguistic boxes': althogh the different grammars use a quite stabil conception system, during my work I realized some shortcomings, as well. It was indispensable to coin some new terms which are presented briefly.

2. Issues related to the classification of different word classes: problems of classification that arose and the solutions offered by me.

2.1. Problems in the classification of noun types: the question of abstractness and concretness. The entry of the noun in the present thesaurus: a lot of nouns -those expressing properties and actions - have been taken out of the abstract category for ontological reasons altough the currently used grammars still put them there.

2.2. Classification criteria for the types of adverbs: grammars classify adverbs according to three criteria. Do all these have to be incorporated in the theasurus and if yes, how? Should any of them have a distinguisehd role, and if yes, on account of what?

2.3. Classification criteria for the types of pronouns and their presentation in the the thesaurus. The same question arose as in the case of adverbs: which criterion is worth taking into account of the ones conventionally applied in the classification of pronouns, should there be a distinguished criterion, and if yes, which one?

2.4. The numeral and the adjective: the elimination of the conceptual category 'numeral' and the contradictions involved; the extension of category 'adjective'. Three types of numerals have been transferred to the category of adjective, at the same time, others are still considered to be numerlas and the term has remained in use. The effect of this modification on the structure of the word class system and its presentation in the thesaurus.

2.5. The classification of auxilaries: grammars approach the subtypes of auxilaries according to different criteria, give different names to them and categorize them differently. How can this be standardized in the thesaurus?

3. Possbilities and potential limitations in the use of the thesaurus.

4. Possibilities of the development of the thesaurus and the necessary preparations for this.