The Collaborative International Dictionary of English v.0.48:

Arousal \A*rous"al\, n.
   The act of arousing, or the state of being aroused.
   [1913 Webster]

         Whatever has associated itself with the arousal and
         activity of our better nature.           --Hare.
   [1913 Webster]

WordNet (r) 3.0 (2006):

arousal
    n 1: the act of arousing; "the purpose of art is the arousal of
         emotions" [syn: arousal, rousing]
    2: a state of heightened physiological activity
    3: awakening from sleep
    4: mutual sexual fondling prior to sexual intercourse [syn:
       foreplay, arousal, stimulation]