1. Not allowing air or gas to pass in or out
   - airtight, air-tight

See also: tight

• entomion
• Ochotona
• Ochotona collaris
• Ochotona princeps
• Ochotonidae
• ochre
• ochrea
• ochreous
• Ochroma
• Ochroma lagopus
• ochronosis
• Ochs
• Ocimum
• Ocimum basilicum
• ocker
• Ockham
• Ockham's Razor
• oconee bells
• ocotillo
• OCR
• oct-
• octa-
• octad
• octadecanoic acid
• octagon