Source : Webster's Revised Unabridged Dictionary (1913)

Prima donna \Pri"ma don"na\; pl. E. {Prima donnas}, It. {Prime
   Donne . [It., fr. primo, prima, the first + donna lady,
   mistress. See {Prime}, a., and {Donna}.]
   The first or chief female singer in an opera.

Source : WordNet®

prima donna
     n 1: a vain and temperamental person
     2: a distinguished female operatic singer; a female operatic
        star [syn: {diva}]