The Collaborative International Dictionary of English v.0.48:
Phenomenal \Phe*nom"e*nal\, a. [Cf. F. ph['e]nom['e]nal.] Relating to, or of the nature of, a phenomenon; hence, extraordinary; wonderful; as, a phenomenal memory. -- Phe*nom"e*nal*ly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
phenomenally adv 1: to a phenomenal degree; "his reaction was phenomenally quick"