touch on in WordNet English dictionary

1. have an effect upon
   "Will the new rules affect me?"
   affect  impact  bear upon  bear on  touch on  touch 
   
2. be relevant to
   "There were lots of questions referring to her talk"; "My remark pertained to your earlier comments"
   refer  pertain  relate  concern  come to  bear on  touch  touch on  have-to doe with 
   
3. restore by replacing a part or putting together what is torn or broken
   "She repaired her TV set"; "Repair my shoes please"
   repair  mend  fix  bushel  doctor  furbish up  restore  touch on 
   
4. refer to or discuss briefly
   touch on