The basic principles and methods outlined are taken from the theory of terminology and practical terminology work. The concepts and their nature are described. A classification of the characteristics, which make up the concepts, is given. The relationships and systems of concepts are demonstrated. The two kinds of definitions that are important for standardization are characterized, together with the requirements for definitions. Three types of linguistic symbols (word, term, and thesaurus word) are described, with emphasis on the constitution and the formation of terms. In addition, the systems of terms and the general requirements for standardized terms are stated. Finally, the methods of standardizing terminologies are mentioned.