How did the letters x and o come to represent hugs and kisses? Let's start with x: the practice of using this letter goes back to the Middle Ages, when it was used by illiterate people to sign documents. X was probably so common due to its simplicity and resemblance to the Christian cross (it was associated with Jesus for a long time before that). After signing, many of those people would kiss the signature to emphasize the importance and religious aspect of the mark, and thus the association got formed. The o part of it is a bit more obscure. It might have something to do with Jewish immigrants to the United States, who signed it with an o to not use the cross, or with shopkeepers who signed that way. It could've been formed as a contrast to the x, or adopted because of an aesthetic similarity to what a hug looks like, or just taken from tic-tac-toe. A lot of that is speculative, but any one of those origins would be fascinating if correct.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd