1. Having two axes
   - biaxial, biaxate

See also: axis

• oreo cookie
• Oreopteris
• Oreopteris limbosperma
• Oreortyx
• Oreortyx picta palmeri
• Orestes
• Orff
• organ
• organ donor
• organ loft
• organ of Corti
• organ of hearing
• organ of speech
• organ pipe
• organ stop
• organ transplant
• organ-grinder
• organdie
• organdy
• organelle
• organic
• organic brain syndrome
• organic chemistry
• organic compound
• organic disorder