Introduction. Among Mari hospitality is considered one of the important factors in maintaining family and good neighbourly relations, therefore, one of the most important places in the concept sphere of the Mari language is occupied by the concept una ‘guest’. Purpose. The purpose of the article is a semantic-cognitive analysis of the structure of the concept una ‘guest’. Materials and methods. The object of study is the description of ceremonies, guest songs and proverbs. The conceptual analysis is carried out using semantic-cognitive, descriptive methods, and contextual analysis. Results, discussion. The figurative, encyclopedic and interpretative fields of the concept una were subjected to analysis. Visual figurative signs emphasize the appearance of the guests. The performance of feast songs is brought to the forefront by the audio images; the ability to conduct a pleasant conversation and perform traditional songs is significant in the image of a guest. The cognitive figurative component demonstrates respect for guests. In the evaluation zone of the concept una ‘guest’, such components as general and aesthetic evaluation are presented. The encyclopedic zone reflects the reasons and goals of guests’ arrival. The utilitarian zone demonstrates that the guests enable the hosts to show hospitality, the ability to observe rituals. The largest number of components is represented in the regulatory zone: hosts should invite, meet and regale the guests, to honor the honored guests, but at the same time to receive all guests with the same hospitality; give them songs and gifts; drive to visit relatives; properly see the guests off. The socio-cultural zone unites all other concept zones, since each of the zones is marked by traditions and rituals. Conclusion. The concept una ‘guest’ is one of the sustainable, actively broadcast. It contains important cultural information, it is a reflection of the system of attitudes and values of the Mari people.