Today I saw this word — hitherto — then I searched in the dictionary to find that it means "up until that time". It looks a little weird since my first seen, and I rarely see words ending with ‑to except to, auto and tomato which look more normal.
I found all words ending with to from here, but this site only says words ending with to are good for playing "Words with Friends" word game. Maybe because my native language is not English, I know almost nothing about all the words listed on that site, so I wonder if the ending ‑to has some common special meaning? If yes, it can help me to remember the words that end with to.