A Russian member of the liberal minority group that advocated gradual reform and opposed the Bolsheviks before and during the Russian Revolution WordNet 3.0 & Open English WordNet

The Mensheviks were a faction of the Marxist Russian Social Democratic Labour Party which split with Vladimir Lenin's Bolshevik faction at the Second Party Congress in 1903. Wikipedia

Political faction Wikidata

A member of the gradualist or moderate wing of the Russian Social Democratic Workers' Party during the years preceding the Russian Revolution, when they split with the Bolsheviks; or a member of a later independent moderate-Marxist party formed in 1917. Wiktionary

Member of a faction of the Russian revolutionary movement. Wiktionary (translation)