orga - pain
- organ
- organella
- organic murmur
- organic paralysis
- organic psychopathy
- organoid tumour
- organum vestibulocochleare
- organ]
- orifice of nasolacrimal duct
- Ornithosis
- ornithosis miningitis
- ornithosis pneumonia
- oroya fever
- orthocheilia
- orthodontic apparatus
- orthodontic appliances
- Orthodontic appliances
- Orthodontic [methods of] treatment
- orthodoxical sleep
- orthogenic occlusion
- orthognatic occlusion
- orthopantomography
- orthopedic workshop
- Orthopedics
- orthopedist
- orthopnea
- orthostatic collapse
- orthotoluidine method
- Ortner's symptom
- Ortodontic and ortopedic [methods of] treatment
- OS (OR)
- oscillography
- Osgood-Schlatter's disease
- osseous defect
- osseous fragment
- osseous hyperparathyrosis
- osseous labyrinth
- osseous syndactyly
- osseous tissue of the alveolus
- osseous-articular system
