- osteoblastoma
- osteochondroma
- one who has lost his memory
- one's effort to succeed
- osteo_sclerosis
- orthopaedic appliance
- on average
- orthopaedic shock
- on terms
- out of bashfulness
- on intimate terms
- one of the old school
- ophthalmoplegic migraine
- one whose days are numbered
- one whose eyes are red (with anger etc)
- one who has but one habitat
- omni_directional antenna
- on_line (online)
- ohio state university
- ossicular
- ossiculate
- occipitotemporal
- on feet
- olericulture
- on the verge of a take off
- open addressing
- oocyte
- organic heperinsulinism
- one fold
- on hand
- one night stand
- or wherever
- on the average
- on a shoestring
- one who does not keep one's pledge
- on the defensive
- one of the principal forms of modern hindustani classical vocal music
- one_spot
- one's integrity to be in danger
- origen
- opisthion
- on the wrong side of the tracks
- open top oxygen tent
- open contact tone
- open loop system
- oliver ellsworth
- on camera
- on second thought
- one's foot
- one's luck to change its course