ORMC - Pacinian corpuscle
- orthomolecular
- orthomolecular medicine
- orthomolecular psychiatry
- orthomolecular therapy
- orthomorphia
- Orthomyxoviridae
- orthomyxovirus
- orthoneutrophil
- orthopaedic
- orthopaedic, orthopedic
- Orthopaedics
- Orthopaedist
- orthopaedist, orthopedist
- orthopantograph
- Orthopantomograph
- orthopedic
- Orthopedic Association; American Orthopsychiatric Association; American Osteopathic Association; ascending aorta
- orthopedic surgery
- Orthopedics
- Orthopedist
