1. Off work, but available to provide a service if requested
   "I'm on call for my patients 4 days a week and every fourth weekend"

Encyclopedia: On call

• occupy
• occur
• occurrence
• occurrent
• ocean
• ocean bottom
• ocean current
• ocean floor
• ocean liner
• ocean perch
• ocean pout
• Ocean State
• ocean sunfish
• ocean trip
• oceanaut
• oceanfront
• oceangoing
• Oceania
• oceanic
• oceanic abyss
• oceanic bird
• oceanic bonito
• oceanic whitetip shark
• Oceanica
• Oceanid