The dynamics of the society and information technologies evolution has a significant impact on all spheres of human life, allowing to develop and expand the range of services provided. This trend is also typical for the library field of activity, where the range of services provided to users is also growing; it actualizes essence and meaning studies of the term “library and information service”. The purpose of the article is to consider the main approaches to the term “library and information service”, taking into account the influence of information technologies and sociocultural factors on the society. To achieve this goal, the analysis of the most famous and frequently encountered 31 concepts has been carried out. The presented definitions are reflected in the current GOSTs for librarianship, current reference and educational literature, as well as in the author’s interpretations of librarians. The analysis has showed that scientists have been revising approaches to the term for many years, but there is still no comprehensive formulation revealing the latest achievements and the essence of library and information services. The terminological analysis has made it possible to identify the genesis of library innovations and to predict the direction of changes in the field of library and information services. It has been concluded that library services are multifaceted actions aimed not only at meeting the user’s needs in various library, information, sociocultural requests in the online and offline space, but also at providing for temporary use the unique equipment for self-realization of one’s creative and educational potential.