Soviet Union (1922-1991); abbreviation for 苏维埃社会主义共和国联盟 sū​wéi'āi​shè​huì​zhǔ​yì​gòng​hé​guó​lián​méng

Connects a describing word or phrase to the noun it describes, similar to 的 de but used in formal or literary writing.

(bound form) friend; companion; associate; partner

(bound form) an organized body, agency, club, or association; also refers to a group of people sharing a common interest or purpose