The Collaborative International Dictionary of English v.0.48:

Excitation \Ex`ci*ta"tion\n. [L. excitatio: cf. F. excitation.]
   1. The act of exciting or putting in motion; the act of
      rousing up or awakening. --Bacon.
      [1913 Webster]

   2. (Physiol.) The act of producing excitement (stimulation);
      also, the excitement produced.
      [1913 Webster]

WordNet (r) 3.0 (2006):

excitation
    n 1: the state of being emotionally aroused and worked up; "his
         face was flushed with excitement and his hands trembled";
         "he tried to calm those who were in a state of extreme
         inflammation" [syn: excitement, excitation,
         inflammation, fervor, fervour]
    2: the neural or electrical arousal of an organ or muscle or
       gland [syn: excitation, innervation, irritation]
    3: something that agitates and arouses; "he looked forward to
       the excitements of the day" [syn: excitation, excitement]