saltire (n.) Look up saltire at Dictionary.com
c.1400, an ordinary on a shield or flag like a St. Andrew's Cross, from Middle French saultoir, literally "stirrup," from Medieval Latin saltatorium, properly neuter of Latin saltatorius "pertaining to leaping," from salire "to leap" (see salient). The connection between a stirrup and the diagonal cross is perhaps the two deltoid shapes that comprise the cross.