1. (mathematics) any of five axioms that are generally recognized as the basis for Euclidean geometry
   - Euclid's postulate, Euclidean axiom

Type of: axiom

• orography
• oroide
• orology
• Orono
• Orontium
• Orontium aquaticum
• oropharyngeal
• oropharynx
• orotund
• orotundity
• Orozco
• orphan
• orphan site
• orphanage
• orphaned
• orphanhood
• orphans' asylum
• orphenadrine
• Orpheus
• orphic
• orphrey
• orpiment
• orpin
• orpine
• Orpington