The Collaborative International Dictionary of English v.0.48:

Cowage \Cow"age\ (kou"[asl]j), n. (Bot.)
   See Cowhage.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cowhage \Cow"hage\ (kou"h[asl]j), n. [Cf. Hind. kaw[=a]nch,
   ko[=a]nch.] (Bot.)
   A leguminous climbing plant of the genus Mucuna, having
   crooked pods covered with sharp hairs, which stick to the
   fingers, causing intolerable itching. The spicul[ae] are
   sometimes used in medicine as a mechanical vermifuge.
   [Written also couhage, cowage, and cowitch.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

cowage
    n 1: pods of the cowage plant or the stinging hairs covering
         them; used as a vermifuge when mixed with e.g. honey
    2: the annual woody vine of Asia having long clusters of
       purplish flowers and densely hairy pods; cultivated in
       southern United States for green manure and grazing [syn:
       cowage, velvet bean, Bengal bean, Benghal bean,
       Florida bean, Mucuna pruriens utilis, Mucuna
       deeringiana, Mucuna aterrima, Stizolobium deeringiana]