Source : Webster's Revised Unabridged Dictionary (1913)

Preferably \Pref"er*a*bly\, adv.
   In preference; by choice.

         To choose Plautus preferably to Terence. --Dennis.

Source : WordNet®

preferably
     adv : more readily or willingly; "clean it well, preferably with
           warm water"; "I'd rather be in Philadelphia"; "I'd
           sooner die than give up" [syn: {sooner}, {rather}]