From Old East Slavic *dружьба*, derived from *друг* (drug, "friend"), which traces back to Proto-Slavic *drugъ* ("companion, other"). Cognates exist across Slavic languages: Polish *druh*, Czech *druh*. The Proto-Slavic root is likely connected to Proto-Indo-European *dʰrewgʰ-* ("to be firm, solid"), reflecting the idea of a steadfast companion.

Friendship (дружба) holds a particularly deep cultural resonance in Russian life and literature. Russian culture traditionally distinguishes between a mere знакомый (acquaintance) and a настоящий друг (true friend) — the latter implying an almost unconditional bond. The word also carries Soviet-era connotations: «Дружба народов» ("Friendship of Peoples") was an official slogan promoting ethnic unity across the USSR. A famous Russian proverb sums up the cultural weight: «Старый друг лучше новых двух» — "An old friend is better than two new ones."