The Collaborative International Dictionary of English v.0.48:
Senhor \Se*nhor"\, n. [Pg. Cf. Se[~n]or, Senior.] A Portuguese title of courtesy corresponding to the Spanish se[~n]or or the English Mr. or sir; also, a gentleman. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
Senhor n 1: a Portuguese title of respect; equivalent to English `Mr'