- See William Faulkner 参见 威廉 Faulkner
- Orthodox Judaism
- orthodox sleep
- orthodoxy
- orthoepies
- orthoepist
- orthoepists
- orthoepy
- orthogenesis
- orthogonal
- orthogonal projection
- orthogonals
- orthographic
- orthographical
- orthographic projection
- orthographies
- orthography
- orthomolecular
- orthopaedics
- orthopedics
- orthopsychiatry
- orthopteran
- orthopterans
- orthoptics
- orthorhombic
- orthoscopic