Source : Webster's Revised Unabridged Dictionary (1913)

Considerably \Con*sid"er*a*bly\, adv.
   In a manner or to a degree not trifling or unimportant;
   greatly; much.

         The breeds . . . differ considerably from each other.
                                                  --Darwin.

Source : WordNet®

considerably
     adv : to a great extent or degree; "I'm afraid the film was well
           over budget"; "painting the room white made it seem
           considerably (or substantially) larger"; "the house has
           fallen considerably in value"; "the price went up
           substantially" [syn: {well}, {substantially}]