The first book of the trilogy is devoted to the study of the social terms of Ancient Rus'. The terms of kinship, social and everyday relations that have developed in Rus' over several centuries are described. The change in the meaningful meaning of words shows the transformation of the social environment of existence, reflected in the consciousness of a medieval person. The concepts of people, state, society, numerous forms of expression of friendly, neighborly or hostile ties, attitudes towards the world, country and land, ideas about life, illness and death, assessment of a person, people and peoples according to their affiliation - all this is shown on the material of ancient Russian sources and in connection with classical works on the history of the Eastern Slavs. The book is intended for a wide range of readers interested in the history of the Russian word.