xyston
A type of long thrusting lance, used in ancient Greece.
The Companions, like the Thessalian cavalry, were a well-mounted force armed with cuirass and the short thrusting spear (xyston) for close combat.
Where it comes from
Borrowed from Ancient Greek ξυστόν (xustón, “spear, javelin”), of unknown origin. Potentially from Proto-Indo-European *ǵʰasto- or *ǵʰasdʰo- (“branch ~ spear, sharp spine”) (whence also gad, goad, and yard), but this is likely a substrate word in view of the various irregularities.
Adapted from the Wiktionary entry xyston (CC BY-SA 4.0).