The Collaborative International Dictionary of English v.0.48:

Grandee \Gran*dee"\, n. [Sp. grande. See Grand.]
   A man of elevated rank or station; a nobleman. In Spain, a
   nobleman of the first rank, who may be covered in the king's
   presence.
   [1913 Webster]

WordNet (r) 3.0 (2006):

grandee
    n 1: a nobleman of highest rank in Spain or Portugal