Chevalier: In the old days, a chevalier was a knight. This definition is now considered obsolete.
Instead, a chevalier is now a gallant, or chivalrous man.
A chevalier can also be someone who keeps their word.
You can see the root meaning if you look closely. After all, certain knights swore to keep the chivalric code. They would protect the weak, fight for honor, defend the helpless, and of course, allow none to pass.
Chevalier comes from the Latin word caballarius, meaning, a horseman. Caballarius comes from the Latin word for horse, caballus.
Brace yourself. Third grade joke:
How does a chevalier read in bed? He uses a knight light!
(I warned you.)