Why 'XOXO' Means 'Hugs and Kisses'

Using an X to symbolize a kiss is older than using an O to symbolize a hug, and given that kissing started as a religious activity instead of a romantic activity, the symbols may have their roots in religious practices.

Why is an X a kiss?

The earliest citation for X as a kiss in the Oxford English Dictionary is from 1763, and the highly quotable Winston Churchill used it in 1894, but he also felt the need to define it. He signed a letter
(Many kisses.) xxx

One theory is that if you use your imagination, an X looks like two people kissing, like a mouth on the left (>) meeting a mouth on the right (<) to create the complete X.

And as I wrote about a few years ago, that’s why you shouldn’t get upset about people writing “Xmas” for “Christmas.”There’s also a religious theory. The letter X has been a symbol for Christ since the time of the Greeks because it’s the first letter of the Greek word for Christ, “Christos.” (ΧΡΙΣΤΟΣ) 

As the book “Kiss and Tell” says, “In the days of early Christianity,  when most humans didn’t know how to write, people would sign important documents … with an X instead of a signature. The X pulled double duty, symbolizing Christ’s cross, as well as his name … The signer would then kiss the document as an oath of sincerity.” So the theory is that through this act, kissing an X, the X became associated with kissing. 

I find that theory less convincing since, at least according to the OED, it seems like using the X to symbolize a kiss is a lot more recent than early Christian times, but it’s still an interesting bit of history.
Why is an O a hug?
Using an O to symbolize a hug is much newer, at least according to the OED, which shows the first use in 1948. The O also seems to be used to symbolize a hug only in combination with an X—never alone.

The theories about why an O symbolizes a hug seem even more made up than those for the X.

People say that maybe it looks like arms circling something in a hug. Or that Jewish immigrants used the O to sign documents much like Christians used the X. 

I’ve never seen anyone else talk about this idea, but I wonder if it comes from tic-tac-toe. That game uses X’s and O’s, so the two symbols go together in many people’s minds. If an X means a kiss, it’s not a stretch to me to imagine that its partner from tic-tac-toe could symbolize a hug to go with it.
Do all cultures kiss?
An interesting bit history I came across while researching the XO-symbol is that kissing on the mouth isn’t universal. Not all cultures do it. It was primarily a western civilization thing, at least until modern times when western civilization started spreading its culture around the world. According to the book “History of the Kiss” kissing didn’t even start out as a romantic gesture. There are definitely cultures that view romantic kissing on the mouth as bizarre or even disgusting, and it definitely started out as more of a religious thing.

Again, according to “History of the Kiss,” Mesopotamians blew kisses “as a means to gain the favor of gods. [And] early Christians greeted one another with a ‘kiss of peace,’ which was believed to carry the soul of the kisser, thus connecting him or her spiritually to the other. … Hindus kiss the ground of a temple to acknowledge its sacredness and purity, and Jews kiss the Western Wall of the Holy Temple in Jerusalem.” All the cool kids are doing it!

So whether you’re swapping candy hearts with X’s and O’s on them this Valentine’s day, or typing XOXO in Facebook comments, now you have a better idea of why those letters symbolize hugs and kisses.