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

See also: operative

• tonality
• tonally
• tondo
• tone
• tone arm
• tone deafness
• tone down
• tone ending
• tone language
• tone of voice
• tone poem
• tone system
• tone up
• tone-beginning
• tone-deaf
• toned
• Tonegawa Susumu
• toneless
• tonelessly
• toneme
• Hastinapura
• hastiness
• Hastings
• hasty
• hasty defence