This is an irregular feature - both in frequency and oddness - dedicated to a word I came across that I have never previously used.
saltire (SAHL-teer) n. An X-shaped cross with diagonal bars of equal length; (heraldry) an ordinary in the shape of Saint Andrew's cross, formed by the crossing of a bend and a bend sinister; the national flag of Scotland, featuring a white diagonal cross on a blue background.
Saltire comes to modern English via a curious path, most recently from the Middle English sautour and Old French saultoir, both of which mean "stile," and tracing its roots back to the Latin saltare ("to jump").
Scottish tradition holds that in 832 CE a decisive battle was fought near Athelstaneford. A combined army of Picts and Scots under the King of Alba, Óengus mac Fergusa, led an invasion into Northumbrian territory.
Unfortunately for Angus, his forces were surrounded by a much larger army of Angles and Saxons, and the king turned to prayer. Angus claimed he received a divine sign when he saw above him a blazing white cross like that associated with the martyr St. Andrew. The king vowed that if he secured victory, then Andrew would then become the patron saint of Scotland and his saltire cross would be forever the flag of Scotland.