come on in WordNet English dictionary

1. develop in a positive way
   "He progressed well in school"; "My plants are coming along"; "Plans are shaping up"
   progress  come on  come along  advance  get on  get along  shape up 
   
2. move towards
   "We were approaching our destination"; "They are drawing near"; "The enemy army came nearer and nearer"
   approach  near  come on  go up  draw near  draw close  come near 
   
3. occur or become available
   "water or electricity came on again after the earthquake"
   come on 
   
4. appear or become visible; make a showing
   "She turned up at the funeral"; "I hope the list key is going to surface again"
   come on  come out  turn up  surface  show up 
   
5. start running, functioning, or operating
   "the lights went on"; "the computer came up"
   go on  come up  come on 
   

come on in English Wiktionary