GNU Collaborative International Dictionary of English

Found one definition

1.       
   Mainor , n. [Anglo-Norm. meinoure, OF. manuevre. See Maneuver.] (O. Eng. Law) A thing stolen found on the person of the thief.
   1913 Webster
   ☞ A thief was said to be “taken with the mainor,” when he was taken with the thing stolen upon him, that is, in his hands.
   Wharton. Bouvier.
   
   1913 Webster