- on the books of
- otic
- osteodystrophy
- osteogenic
- one who avenges
- oujda
- ounce
- one condemned to a slog
- on any account
- on either hand
- one meant chiefly to provide a company
- one hundred thousand
- one hundred seventy_five
- oral rehydration therapy
- on one's guard
- on your guard
- organotin
- oxidase
- opium act
- odist
- onomastics
- one who commits incest with one's mother
- object phase
- output process
- output program module
- one who sets forth or enunciates
- oxyuricide
- oriented
- one tenth
- orbitothalamic tract
- old age pension
- one_eyed person
- optically empty
- office holder
- official pharmacopoeia
- office_bearer
- officeholder
- orthoglycaemic
- oligaemic
- oppressively
- oppressiveness
- oligarchical
- one who delivers religious discourses
- operable
- operating
- outgoer
- old_man_of_the_woods
- one who renounces
- on the warpath
- onymous