Apr 5, 2025 buckminsterfullerene ˈbək-(ˌ)min-stər-ˌfu̇-lə-ˈrēn 6 syllables very rare noun.a spherical fullerene C60 that is an extremely stable form of pure carbon, consists of interconnected pentagons and hexagons suggestive of the geometry of a geodesic dome, and is believed to be a major constituent of soot Origin R. Buckminster Fuller.