Hugs and kisses, abbreviated in the Anglosphere as XO or XOXO, is an informal term used for expressing sincerity, faith, love, or good friendship at the end of a written letter, email or text message.
A 2014 article in The Washington Post that drew on interviews with scholars noted that "the Internet abounds with origin theories" yet that "there is no definitive answer to how a cross came to mean a kiss" and even that "less is known about how 'o' came to signify a hug".
Allegedly, in the Middle Ages, a Christian cross might be drawn on documents or letters to mean sincerity, faith, and honesty; the sign was certainly sometimes used in place of a signature.
[3] Unscholarly speculations sometimes extend to the idea that after a cross was written at the end of a document, the writer might kiss it as a show of their sincerity.
[4] The Greek word for Christ, ΧΡΙΣΤΟΣ, gave rise to the practice of using the Latin letter X as an abbreviation for 'Christ' (similar to the more elaborate Chi Rho symbol).