Decode the parts: 脱 ('remove') + 氧 ('oxygen') + 核 ('nucleus') + 糖 ('sugar') = 'oxygen-removed nucleus-sugar' = deoxyribose. Compare with 核糖 ('ribose'), the sugar in RNA - the only difference is one missing oxygen atom, exactly what 脱氧 announces.
usage
DNA's full Chinese name is 脱氧核糖核酸 ('deoxyribonucleic acid'). High-school biology textbook vocabulary.
