XOXO is slang in the English language and means "hugs and kisses", which is translated to "kisses and hugs" in Portuguese. It is often used to close informal messages, exchanged mainly between close friends.
The origin of the slang is not known for sure, however there are some interpretations that help to create a relationship between XOXO and the act of kissing and hugging. Some people consider the X as a representation of two lips touching, ie two people kissing. already the letter O would correspond to four arms forming an embrace.
Another analysis shows the X as the representation of open arms (prepared to hug someone), while the O it would be the shape of a mouth when kissing. Another theory says that the relationship of the letter "X" with kissing dates back to the Middle Ages. At that time, many people drew a cross (Christian symbology) at the end of their letters and then kissed it, as a sign of sincerity, honesty and faith. Likewise, some documents were signed in this way by people who could not write.
In Brazil, the use of XOXO at the end of text messages, in reference to English custom, it became popular from the North American series gossip Girl (2007 - 2012), where slang was constantly mentioned.