Russel-Saunders coupling
罗素–桑德斯耦合

• observation window
• observatory
• observeing scaffold
• observer
• observing ine
• obstacele avoidance laser system
• obstacle avoidance sensor
• obstruction
• obtainable accuracy
• obtuse
• obtuse angel
• occulation
• occulting disk
• occupancy
• occupied electron state
• occupied state
• occuption number
• ocean environment
• oceanography
• ocean optics
• ocellus
• ochre
• ocsillator strenght
• octagon
• octagonal prism