verb (v)

• make broader(verb.change)

  Example:
  Broaden the road.
  

  source: wordnet30
• extend in scope or range or area(verb.change)

  Example:
  Broaden your horizon.
  

  Synonym:
  extend, widen
  

  source: wordnet30
• vary in order to spread risk or to expand(verb.change)

  Synonym:
  branch out, diversify
  Antonym:
  narrow, narrow down, specialise, specialize
  

  source: wordnet30
• become broader(verb.change)

  Example:
  The road broadened.
  

  source: wordnet30
• To grow broad; to become broader or wider.(verb)

  source: webster1913
• To make broad or broader; to render more broad or comprehensive.(verb)

  source: webster1913