saltire

noun Heraldry.

1. 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.

noun

1. heraldry an ordinary consisting of a diagonal cross on a shield

n.c.1400, an ordinary that resembles a St. Andrew’s Cross on a shield or flag, consisting of a bend dexter and a bend sinister crossing each other, from Middle French saultoir, literally “stirrup,” from Medieval Latin saltatorium, properly neuter of Latin saltatorius “pertaining to leaping,” from salire “to leap” (see salient (adj.)). The connection between a stirrup and the diagonal cross is perhaps the two deltoid shapes that comprise the cross.