EN
The purpose of this paper is to explicate essential terms related to ethnicity. It contains definitions of such terms as nation, ethnicity, ethnic group, ethnographic group, ethnic minority, assimilation. Also, the paper presents an outline of the ethnicity building process and touches upon the issue of native tongue as a criterion defining ethnic membership. Additionally, the paper contemplates the correlation between the declared native language and religious denomination. The analytical database used for the purpose of this paper are Polish and foreign reference resources, as well as sociological and historical literature.