a man of social authority and dignity; a lord; a master; a gentleman; -- in this sense usually spelled sire.-a title prefixed to the christian name of a knight or a baronet.-an english rendering of the latin dominus, the academical title of a bachelor of arts; -- formerly colloquially, and sometimes contemptuously, applied to the clergy.-a respectful title, used in addressing a man, without being prefixed to his name; -- used especially in speaking to elders or superiors; sometimes, also, used in the way of emphatic formality.