Coursers are commonly believed to be named for their running gait, (from Old French cours, 'to run'.). However, the word possibly derived from the Italian corsiero, meaning 'battle horse'.
The courser was more common than the destrier, and preferred for hard battle as they were light, fast and strong. They were valuable horses, but less expensive than the highly-prized destrier. Another horse commonly ridden during war was the rouncey, which was an all-purpose horse.