Probably their steed. I doubt they'd use the horses real name.
knights rode horses like any other person would ride a horse
The squire. The squire would carry the knights weapons or armor, hold any prisoner the knight might take, protecting the knight, and take care of the knights horses.
Horses did not live whith Knights.
they fighted on horses
Knights were skilled horsemen and often rode horses into battle, but not all knights had horses. Some knights who could not afford a horse would fight on foot.
tall and strong ones like quarter horses. Depends on the knights.
The Heavy Horse
Horses
Friesian horses were popular war horses, and mounts of knights. For the Howrse game for Archimedes the answer is "for carrying knights".
Horses were important to knights. In fact special heavy horses were bred for them.
Seeing as to how each side starts with two knights (horses) there are four knights at the start of the game. If a pawn is promoted to a knight there can be more than four knights on the board, but this doesn't usually happen.
Carried knights into battle and trampled people.