O字母开头的单词或词组(第13页)：
- occult
- ode
- odious
- odium
- odometer
- offence(offense)
- offbeat
- offend
- offensive
- offhand
- onset
- officious
- off-key
- offset
- offish
- offspring
- offstage
- ogle
- ointment
- oligarchy
- omelet
- olfaction
- ominous
- omnipresent
- omit
- omnipotent
- omniscient
- onerous
- opacity
- opalescence
- opaque
- operative
- operetta
- opine
- opinionated
- opponent
- opportune
- oppose
- oppress
- opprobrious
- optimism
- optimist
- optimum
- optional