“骑士”的英语怎么说?是指中世纪的骑士

Knight is great answer and common used.

knight
(欧洲中世纪的)骑士；武士，勇士〔尤指打仗或比武时作贵妇人侍从或斗士的人〕

knight

Chevalier

骑士:rider
Relative explainations:

Examples:
1.你听说过夜间飘过的幽灵骑士的故事吗?
Have you heard the story of the phantom riders passing by in the night?
2.骑士迫使他的马在暴风雨中前进.
The rider forced his horse on through the storm.
3.那位骑士被他的敌人谋杀了.
The knight was murdered by his foes.
4.骑士发誓要为他父亲向敌人报仇.
The knight swore he would revenge his father's death.
5.骑士们冲向宫殿去保护国王.
The knights rushed into the palace to protect their king.
6.骑士们在小酒店里会合,讨论他们的计划.
The knights met in the tavern to discuss their plan.
7.那个骑士用刀刺穿他的对手.
That knight ran his sword through his opponent.
chivalric education
骑士教育
Knights Insurrection
骑士暴动
A Knight Templar.
圣殿骑士
The black knight.
黑衣骑士
A knight's page.
骑士的侍童
A gentle knight.
勇武的骑士
Knights of Teutonic Order
条顿骑士团
chivalric rites; the knightly years.
骑士礼仪；骑士时代.
Ceremonial bestowal of knighthood.
骑士授予礼授予骑士称号的仪式
A mounted soldier; a knight.
骑士骑在马上的士兵；骑士