obstruction caveobstruction moraineobtect pupaobtuseobtuse angle blockobtuse bisectrixoccidentaloccipital condyleoccipital furrowoccipital ringoccipital sutureocciputoccludeoccludent marginocclusor lamina or lamina or laminaocclusor muscleoccult mineraloccultationoccupancyoceanocean current or ocean currents or ocean currentsocean floor spreading or ocean floor or ocean floorocean hole or blue hole or blue holeocean or floorocean or floor metamorphismoceaniaoceanic crust or crust or crustoceanic formationoceanic islandoceanic plateauoceanic ridgeoceanic riseoceanic trench or oceanic trenches or oceanic trenchesoceaniteoceanography or oceanolography or oceanolographyoceanologyocellarocellar bristle or ocellar bristles or ocellar bristlesocellar triangleocellusocherocherous or ochreous or ochreous or ochrousochoanochreochreousochric epipedonoctactineoctahedraloctahedral cleavage or cleavage or cleavageoctahedral coordination
