1. Belonging to or existing in times before recorded history
   - prehistoric

See also: past

• obturate
• obturation
• obturator
• obturator vein
• obtuse
• obtuse angle
• obtuse leaf
• obtuse triangle
• obtuse-angled triangle
• obtusely
• obtuseness
• obverse
• obvert
• obviate
• obviating
• obviation
• obvious
• obviously
• obviousness
• oca
• ocarina
• Occam
• Occam's Razor
• occasion
• occasional