The Collaborative International Dictionary of English v.0.48:

Diva \Di"va\ (d[=e]"v[.a]), n.; It. pl. Dive (d[=e]"v[=a]).
   [It., prop. fem. of divo divine, L. divus.]
   A prima donna.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

diva
    n 1: a distinguished female operatic singer; a female operatic
         star [syn: prima donna, diva]