The Collaborative International Dictionary of English v.0.48:
Preferably \Pref"er*a*bly\, adv. In preference; by choice. [1913 Webster] To choose Plautus preferably to Terence. --Dennis. [1913 Webster]WordNet (r) 3.0 (2006):
preferably adv 1: 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: preferably, sooner, rather]