The Collaborative International Dictionary of English v.0.48:

Questor \Ques"tor\, n. [L. quaestor, contr. fr. quaesitor, fr.
   quaerere, quaesitum, to seek for, ask: cf. F. questeur.]
   (Rom. Antiq.)
   An officer who had the management of the public treasure; a
   receiver of taxes, tribute, etc.; treasurer of state.
   [Written also qu[ae]stor.]
   [1913 Webster]

   Note: At an early period there were also public accusers
         styled questors, but the office was soon abolished.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Quaestor \Qu[ae]s"tor\, n. [L.]
   Same as Questor.
   [1913 Webster]

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

QUAESTOR. The name of a magistrate of ancient Rome.