Source : Webster's Revised Unabridged Dictionary (1913)

Patroness \Pa"tron*ess\, n. [Cf. F. patronnesse.]
   A female patron or helper. --Spenser.

         Night, best patroness of grief.          --Milton.

Source : WordNet®

patroness
     n : a woman who is a patron or the wife of a patron [syn: {patronne}]