odor - ORM
- opening of nasolacrimal duct
- opening of pulmonary trunk
- opening of sphenoid sinus
- opening of superior vena cava
- opening of vermiform appendix
- opening of vestibular canaliculus
- opening snap
- Opening, vaginal
- openings of papillary ducts
- openings of pulmonary veins
- opera-glass hand
- operable
- operant
- operant behavior
- operant conditioning
- operate
- operating
- operating field
- operating microscope
- Operating room
- operating theatre
- Operation
- Operation, Blalock-Taussig
- Operation, Macewen
- operative
- operative cholangiography
- operative dentistry
- operative myxedema
- operative surgery
- operator
- operator gene
- operator locus
- operatory
- opercula
- opercula of insula
- opercular
- opercular fold
- opercular part of middle cerebral artery
- operculate
- operculated
