an ordinary in the form of a cross with arms running diagonally from the dexter chief to the sinister base and from the sinister chief to the dexter base; St. Andrew's cross.
Idioms
2.
in saltire, (of charges) arranged in the form of a saltire.
3.
per saltire, diagonally in both directions: party per saltire.
c.1400, an ordinary on a shield or flag like a St. Andrew's Cross, from M.Fr. saultoir, lit. "stirrup," from M.L. saltatorium, prop. neut. of L. 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.