1. The first day of each month in the ancient Roman calendar

Encyclopedia: Calends

• orb-weaving spider
• orbicular
• orbiculate
• orbiculate leaf
• Orbignya
• Orbignya cohune
• Orbignya martiana
• Orbignya phalerata
• Orbignya spesiosa
• Orbison
• orbit
• orbit period
• orbital
• orbital cavity
• orbital motion
• orbital plane
• orbital point
• orbital rotation
• orbitale
• orbiter
• orbitual
• orc
• orca
• Orcadian
• orchard