What is "sarissophoroi"

n. (plural of sarissophoros English)

The sarissophoroi (singular: sarissophoros) were a unit of light cavalry in the army of Macedon and various Hellenistic states. They wielded a shorter version of the infantryman's ( pezhetairos) lance, but also carried javelins so that they may harry an enemy from a distance. This, and their general Thracian provenance, make them akin to the prodromoi cavalry corps. Thracian sarissophoroi served under Alexander the Great in his conquest of Persia, and were also heavily utilized by his successors against each other and the Romans. Their main role was to ride alongside the Companion Cavalry to protect them from enemy light cavalry or missile troops. They rarely wore body armor, but were often known to have worn a helmet; in most sources it is a Phrygian helmet.

Considering that they carry the sarissa, the sarissophoroi had a very powerful charge, devastating to an enemy formation's flanks and rear.