1. Being in effect or operation
   "bus service is in operation during the emergency"
   - operational, operating

See also: operative

• paediatrics
• paedodontist
• paedogenesis
• paedophile
• paedophilia
• paella
• paeon
• Paeonia
• Paeoniaceae
• paeony
• PAGAD
• pagan
• pagan religion
• Paganini
• paganise
• paganism
• paganize
• page
• page number
• page printer
• page-at-a-time printer
• page-turner
• pageant
• pageantry
• pageboy