1. Evening-opening primrose of south central United States
   - Ozark sundrops, Oenothera macrocarpa

Type of: evening primrose

• Ochroma
• Ochroma lagopus
• ochronosis
• Ochs
• Ocimum
• Ocimum basilicum
• ocker
• Ockham
• Ockham's Razor
• oconee bells
• ocotillo
• OCR
• oct-
• octa-
• octad
• octadecanoic acid
• octagon
• octagonal
• octahedral
• octahedron
• octal
• octal digit
• octal notation
• octal number system
• octal numeration system