- orthogonalize
- orthogonally
- orthograde
- orthograph
- orthographer
- orthographic
- orthographic projection
- orthographic view
- orthographical
- orthographical projection
- orthographically
- orthographist
- orthography
- orthohelium
- orthohydrogen
- orthomelic
- orthometric elevation
- orthometric height
- orthomode junction
- orthomorphia
- orthomorphism
- orthonormal polynomial
- orthonormal set
- orthonormal system
- orthonormal vectors
- orthonorrmal
- orthopaedic
- orthopaedics
- orthopaedist
- orthopaedy
- orthopara conversion
- orthopatomogram
- orthopedic
- orthopedic surgery
- orthopedics
- orthopedist
- orthopedy
- orthophony
- orthophoria
- orthophosphate
- orthophosphoric
- orthophrenia
- orthophyre
- orthophyric
- orthopinacoid
- orthoplastocyte
- orthoploidy
- orthopnea position
- orthopneic
- orthopnoea
- orthopnoeic
- orthopole
- orthoprism
- orthoptera
- orthopteran
- orthopterist
- orthopteroid
- orthopteron
- orthopterous
- orthoptic
- orthoptic circle
- orthoptic curve
- orthoptics
- orthoptoscope
- orthoradial
- orthorhombic
- orthorhombic system
- orthorock
- orthoscope
- orthoscopic
- orthoscopic eyepiece
- orthoselection
- orthosilicic
- orthosilicic acid
- orthosomatic
- orthospermous
- orthospiral
- orthostate
- orthostatic
- orthostichous
- orthostichy
- orthotelomitic
- orthotherapy
- orthotics
- orthotopic
- orthotropic
- orthotropic body
- orthotropic deck
- orthotropic materials
- orthotropic plate
- orthotropic shell
- orthotropic structures
- orthotropism
- orthotropous
- orthoxylene
- orthptic circle
- orticant
- ortlerite
- ortolan
- oryctognosy