1. Operated by hand
   - non-automatic

See also: manual

• 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
• occasionalism