- Orthokeratology Noun Adj
- Ortholattice Noun Adj
- Orthology Noun Adj
- Orthometer Noun Adj
- Orthometric Adj
- Orthomodular Adj
- Orthomorphic Adj
- Orthomyxovirus Noun Adj
- Orthonormal Adj
- Orthonormality Noun Adj
- Orthonormalized Adj Past Participle
- Orthooptic Adj
- Orthooptical Adj
- Orthopaedic Adj
- Orthopantomogram Noun Adj
- Orthopantomograph Noun Adj
- Orthopantomography Noun Adj
- Orthopedic Adj Noun
- Orthopedical Adj
- Orthophosphoric Adj Noun
- Orthophotograph Noun Adj Verb
- Orthophotomap Noun Adj
- Orthopneic Adj
- Orthopnoeic Adj
- Orthopolar Adj Noun
- Orthopole Noun Adj
- Orthopoxvirus Noun Adj
- Orthoprojector Noun Adj
- Orthopsychiatric Adj
- Orthopsychiatrical Adj
- Orthopteran Noun Adj
- Orthopterous Adj
- Orthoptic Adj
- Orthoptist Noun Adj
- Orthopyroxene Noun Adj
- Orthorhombic Adj
- Orthorombic Adj
- Orthoscopic Adj
- Orthostatic Adj
- Orthostatometer Noun Adj
- Orthostereoscopic Adj
- Orthostichous Adj
- Orthostochastic Adj
- Orthosymmetric Adj
- Orthosymplectic Adj
- Orthosympletic Adj
- Orthotic Adj Noun
- Orthotics Noun Adj
- Orthotist Noun Adj
- Orthotoluidine Noun Adj
- Orthotopic Adj
- Orthotronic Adj
- Orthotrophic Adj
- Orthotropic Adj
- Orthotropous Adj
- Ortogonal Adj
- Ortolan Noun Adj
- Ortoluidine Noun Adj
- Orwellian Adj
- Oryx Noun Pnoun Adj