martingale (n.)
1580s, from Middle French martingale (16c.), of uncertain origin, perhaps from Old Provençal martegalo, fem. of martegal "inhabitant of Martigue," making the etymological sense "worn in the manner of the people of Martigue;" or perhaps from Spanish almartaga, word for a sort of halter or rein, from Arabic almartak, in which case it might have been influenced in form by the Provençal word.