What is the meaning of on?

adjective

• In operation or operational.
  • usage: "left the oven on"; "the switch is in the on position"
• Of events. ( planned or scheduled)
  • usage: "the picnic is on, rain or shine"; "we have nothing on for Friday night"

adverb

• With a forward motion.
  • usage: "we drove along admiring the view"; "the horse trotted along at a steady pace"; "the circus traveled on to the next city"; "move along"; "march on"
  • synonyms: along
• Indicates continuity or persistence or concentration.
  • usage: "his spirit lives on"; "shall I read on"
• In a state required for something to function or be effective.
  • usage: "turn the lights on"; "get a load on"