The Collaborative International Dictionary of English v.0.48:

Hives \Hives\, n. [Scot.; perh. akin to E. heave.] (Med.)
   (a) The croup.
   (b) An eruptive disease (Varicella globularis), allied to the
       chicken pox.
       [1913 Webster]

WordNet (r) 3.0 (2006):

hives
    n 1: an itchy skin eruption characterized by weals with pale
         interiors and well-defined red margins; usually the result
         of an allergic response to insect bites or food or drugs
         [syn: urtication, urticaria, hives, nettle rash]