The Collaborative International Dictionary of English v.0.48:

Widower \Wid"ow*er\, n.
   A man who has lost his wife by death, and has not married
   again. --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

widower
    n 1: a man whose wife is dead especially one who has not
         remarried [syn: widower, widowman]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

WIDOWER. A man whose wife is dead. A widower has a right to administer to
his wife's separate estate, and as her administrator to collect debts due to
her, generally for his own use.