Saltire

A saltire, also called Saint Andrew's Cross or the crux decussata,^[1] is a heraldic symbol in the form of a diagonal cross. The word comes from the Middle French sautoir, Medieval Latin saltatoria ("stirrup").^[2]

From its use as field sign, the saltire came to be used in a number of flags, in the 16th century for Scotland and Burgundy, in the 18th century also as the ensign of the Russian Navy, and for Ireland. Notable 19th-century usage includes some of the flags of the Confederate States of America. It is also used in the flag of Jamaica and on seals, and as a heraldic charge in coats of arms.

The term saltirewise or in saltire refers to heraldic charges arranged as a diagonal cross. The shield may also be divided per saltire, i.e. diagonally.

A warning sign in the shape of a saltire is also used to indicate the point at which a railway line intersects a road at a level crossing.

^ "Crux decussata". Merriam-Webster Dictionary. Merriam-Webster, Inc. Retrieved July 24, 2018.
^ Heraldic use 13th century (attested 1235, Huon de Méry, Tournoiemenz Antecrist, v. 654). In 1352 also of a particular form of stirrup (Comput. Steph. de la Fontaine argent, du Cange s.v. "saltatoria"). 15th-century use in the sense of a barrier of wooden pegs arranged crosswise, preventing the passage of livestock that can still be jumped by people. "sautoire" in TLFi; see also "saltire" at etymonline.com.

[1] "Crux decussata". Merriam-Webster Dictionary. Merriam-Webster, Inc. Retrieved July 24, 2018.

[2] Heraldic use 13th century (attested 1235, Huon de Méry, Tournoiemenz Antecrist, v. 654). In 1352 also of a particular form of stirrup (Comput. Steph. de la Fontaine argent, du Cange s.v. "saltatoria"). 15th-century use in the sense of a barrier of wooden pegs arranged crosswise, preventing the passage of livestock that can still be jumped by people. "sautoire" in TLFi; see also "saltire" at etymonline.com.

[1]

[2]