睾丸髓样瘤：睾丸的浆细胞瘤- ornithine transcarbamoylase
- ornithine-transcarbamylase (OTC) deficiency
- Ornithodoros
- Ornithonyssus
- ornithosis
- oro-
- orolingual
- oromaxillary
- oromeningitis
- oronasal
- oropharynx
- Oropsylla
- orosomucoid
- orotate phosphoribosyltransferase (OPRT)
- orotic acid
- orotidine 5'-phosphate decarboxylase (ODC)
- orotidine 5'-phosphate pyrophosphorylase
- orotidylate decarboxylase
- orpanoxin
- orphenadrine
- orrho-
- orrhomeningitis
- orris
- Orr treatment (method,technic)
- Orsi-Grocco method