1. Of or relating to or having a fenestra 
2. Of or relating to windows

See also: fenestra, window

• Onopordum
• Onopordum acanthium
• Onosmodium
• onrush
• Onsager
• onset
• onshore
• onside
• onslaught
• onstage
• Ontarian
• Ontario
• ontic
• onto
• ontogenesis
• ontogenetic
• ontogeny
• ontological
• ontologically
• ontologist
• ontology
• onus
• onward
• onward motion
• onwards