The term "Russian" can refer to a few related concepts:

1. Russians as an Ethnic Group: Russians are an East Slavic ethnic group native to Eastern Europe. Their mother tongue is the Russian language, and the majority adhere to Orthodox Christianity. Russians form the largest Slavic and European nation. Historically, they originate from East Slavic tribes and Kievan Rus'. The majority live in Russia, with significant minorities in other post-Soviet states and a large diaspora worldwide.
2. Russian Language: Russian is an East Slavic language of the Balto-Slavic branch of the Indo-European family. It is the most spoken Slavic language and the most geographically widespread language in Eurasia, with over 253 million speakers worldwide. It uses the Cyrillic alphabet, has complex grammar, and is an official language in several countries and international organizations.
3. Adjective Use: "Russian" can also describe anything relating to Russia, its people, or its language.

In summary, "Russian" primarily refers either to the people of Russia, the Russian language, or anything related to Russia as a nation and culture. The Russians as a people have a rich cultural and historical background, and their language is a major global Slavic language with a significant role in international affairs and communication. If you'd like, I can provide further details on any of these aspects.