- Ob
- Ob River
- Obadiah
- obbligato
- obduracy
- obdurate
- obdurately
- obeah
- obeche
- obechi
- obedience
- obedience plant
- obedient
- obedient plant
- obediently
- obeisance
- obelion
- obelisk
- Oberson
- obese
- obesity
- obesity diet
- obey
- obfuscate
- obfuscation
- obi
- obidoxime chloride
- obiism
- obit
- obiter dictum
- obituary
- object
- object ball
- object code
- object glass
- object language
- object lens
- object lesson
- object of a preposition
- object of the verb
- object program
- object recognition
- object-oriented database
- object-oriented database management system
- object-oriented programing
- object-oriented programing language
- object-oriented programming
- object-oriented programming language
- objectification
- objectify
- objection
- objectionable
- objectionableness
- objectionably
- objective
- objective case
- objective lens
- objectively
- objectiveness
- objectivity
- objector
- objet dart
- objurgate
- objurgation
- oblanceolate
- oblanceolate leaf
- oblate
- oblateness
- oblation
- obligate
- obligate anaerobe
- obligated
- obligation
- obligational
- obligato
- obligatorily
- obligatory
- oblige
- obliged
- obliger
- obliging
- obligingly
- obligingness
- oblique
- oblique angle
- oblique bandage
- oblique case
- oblique triangle
- oblique vein of the left atrium
- oblique-angled
- obliquely
- obliqueness
- obliquity
- obliterable
- obliterate
- obliterated
- obliteration
- obliterator
- oblivion
- oblivious
- obliviousness
- oblong
- oblong leaf
- oblong woodsia
- oblongness
- obloquy
- obnoxious
- obnoxiously
- obnoxiousness
- obnubilate
- oboe
- oboe da caccia
- oboe damore
- oboist
- obolus
- obovate
- obovate leaf
- OBrien
- obscene
- obscenely
- obscenity
- obscurantism
- obscurantist
- obscure
- obscurely
- obscureness
- obscurity
- obsequious
- obsequiously
- obsequiousness
- observable
- observably
- observance
- observant
- observantly
- observation
- observation dome
- observation post
- observation station
- observation tower
- observational
- observatory
- observe
- observed
- observed fire
- observer
- observers meridian
- observing
- observingly
- obsess
- obsessed
- obsession
- obsessional
- obsessionally
- obsessive
- obsessive-compulsive
- obsessive-compulsive disorder
- obsessive-compulsive personality
- obsessively
- obsessiveness
- obsessivity
- obsidian
- obsolesce
- obsolescence
- obsolescent
- obsolete
- obsoleteness
- obstacle
- obstacle race
- obstetric
- obstetrical
- obstetrical delivery
- obstetrical toad
- obstetrician
- obstetrics
- obstinacy
- obstinance
- obstinate
- obstinately
- obstipate
- obstipation
- obstreperous
- obstreperously
- obstreperousness
- obstruct
- obstructed
- obstructer
- obstruction
- obstruction of justice
- obstructionism
- obstructionist
- obstructive
- obstructive shock
- obstructively
- obstructor
- obstruent
- obtain
- obtainable
- obtainment
- obtention
- obtrude
- obtrude upon
- obtrusive
- obtrusively
- obtrusiveness
- obtund
- obturate
- obturator
- obturator vein
- obtuse
- obtuse angle
- obtuse leaf
- obtuse triangle
- obtuse-angled triangle
- obtusely
- obtuseness
- obverse
- obviate
- obviating
- obviation
- obvious
- obviously
- obviousness
