www.alphadictionary.com

Does anyone know of a good glossary of idioms/
Does anyone know the origin of the idioms "tie the knot" or "get hitched" (meaning to get married)?
-- Thank you for any insight.

I've always liked The Phrase Finder. It's no longer being added to, but the old stuff is still available and readable. It pre-dates the AI invasion to this kind of site, so it feels human.

It doesn't have Get Hitched, but t'other one's here.

Getting hitched is an extension from hitching your horse to a wagon.

Hitch itself has an interesting origin, too.