The concepts of each subject area, which are interconnected, form a conceptual system of a particular science. The relationship and dependence of special concepts is often manifested in hyper-hyponymic relations. Structures built on the relations of hyper-hyponymy between professional concepts are a complex framework of terminology. The interrelationships between individual language units and between their associations depend on the relation between terms. The study of the processes of formation of hyper-hyponymic relations is one of the central problems of cognitive semantics, as categorization is directly related to the global problem of theoretical linguistics in the ratio of cognitive and linguistic structures. The purpose of the article is to study the specifics of the hierarchical structure of terms to denote animal diseases on the basis of hyper-hyponymic relations and to determine a set of language tools for their expression. Materials and methods of research . Component and distributive analysis were used to study the structure of terms. To establish the semantic connections of words, lexicographic analysis is used, which is based on the principle of using dictionary interpretations, which in most cases are a reliable sources of thematic groups of terminological units. To identify systemic linguistic relations in the studied terminology, we use distributive analysis and the method of semantic oppositions. Results of the research. The construction of a hierarchical structure of terms to denote animal diseases was carried out by analyzing the relationship between the term denoting a common generic concept and a term that reflects the variants of the same concept. In the terminology to denote animal diseases, two directions of term formation were distinguished: differentiation by the place of lesion and by species of animals. The hyperonym Diseases by location is generic to other terms in its group: endocrine and metabolic diseases; hematology, oncology and immunology; dermatological diseases; diseases of the gastrointestinal tract; cardiac and respiratory diseases; diseases of urinary tracts; diseases of reproductive system; neurologic and musculoskeletal disorders; ophthalmological diseases. The second principle of differentiation of terms to denote animal diseases in English is Diseases by animal species. This hyperonym is represented by diseases of certain species of animals. It is established that the analyzed hyper-hyponymic structure of terms has a multilevel organization, which reflects the evolution of the development of this clinical branch of veterinary medicine. Structural analysis of the hierarchical organization of terms to denote animal diseases in English allows not only to have an idea of the content of this subject area, but also to better understand the principles of terminology structure, which is important for lexicographic and translation practice. Conclusions. Terms to denote animal diseases show the relationship of phenomena, processes, objects that correspond to this area of work of veterinarians, and their ordering can be achieved through the correct classification of realities, which create terms based on the selection of hyperonyms and hyponyms. Thus, the regularity of the participation of terminological units in the constant systemic relations of subordination, which are characteristic of the processes of integration or differentiation of their components both at different and at the same levels of their detection, is expressed.