- Orthopoxvirus Subst. Adj.
- Orthopraxia Subst.
- Orthopraxy Subst.
- Orthoprojector Subst. Adj.
- Orthopsychiatric Adj.
- Orthopsychiatrical Adj.
- Orthopsychiatrist Subst.
- Orthopsychiatry Subst.
- Orthopter Subst.
- Orthopteran Subst. Adj.
- Orthopterous Adj.
- Orthoptic Adj.
- Orthoptics Subst.
- Orthoptist Subst. Adj.
- Orthopyroxen Subst.
- Orthopyroxene Subst. Adj.
- Orthorhombic Adj.
- Orthoroentgenography Subst.
- Orthoroentgenometry Subst.
- Orthorombic Adj.
- Orthoscanner Subst.
- Orthoscheme Subst. Adj.
- Orthoscope Subst.
- Orthoscopic Adj.
- Orthosilicate Subst. Adj.
- Orthosis Subst.
- Orthoskiagraphy Subst.
- Orthostatic Adj.
- Orthostatometer Subst. Adj.
- Orthostereoscope Subst.
- Orthostereoscopic Adj.
- Orthostichous Adj.
- Orthostichy Subst.
- Orthostochastic Adj.
- Orthosymmetric Adj.
- Orthosymplectic Adj.
- Orthosympletic Adj.
- Orthotic Adj. Subst.
- Orthotics Subst. Adj.
- Orthotist Subst. Adj.
- Orthotoluidine Subst. Adj.
- Orthotopic Adj.
- Orthotopy Subst.
- Orthotronic Adj.
- Orthotrophic Adj.
- Orthotropic Adj.
- Orthotropism Subst.
- Orthotropous Adj.
- Orthotropy Subst.
- Ortogonal Adj.
- Ortolan Subst. Adj.
- Ortoluidine Subst. Adj.
- Orts Subst.
- Orwellian Adj.
- Oryctology Subst.
- Oryol Eigenn. Adj.
- Oryx Subst. Eigenn. Adj.
- Osages
- Osaka Subst. Eigenn. Adj.
- Oscan Adj. Subst.