adverb (r)

• to a great extent or degree(adv.all)

  Example:
  Painting the room white made it seem considerably (or substantially) larger.
  The house has fallen considerably in value.
  

  Synonym:
  substantially, well
  

  source: wordnet30
• In a manner or to a degree not trifling or unimportant; greatly; much.(adverb)

  source: webster1913