EXCITANT is a 8 letter word that starts with E.

1. \Ex*cit"ant\, a. [L. excitans, -antis, p. pr. of
   excitare: cf. F. excitant.]
   Tending to excite; exciting.
   
   

2. \Ex*cit"ant\, n. (Physiol.)
   An agent or influence which arouses vital activity, or
   produces increased action, in a living organism or in any of
   its tissues or parts; a stimulant.