In what language do they use the number "3" as a letter?

by [deleted]
foreander

Cyrillic script has the letter ze which is written like a 3.

Searocksandtrees

This post has been removed because it's not a history question. You might try the stickied "Q&A" post in /r/Linguistics (don't create your own post there), or /r/AskLinguistics