In the UK, 'X' is commonly used at the end of a message to represent kisses. Similar to 'Xs and Os' (kisses and hugs) in North America, however 'X' can be and is often used by people of varying familiarity (platonic friendships, siblings, crushes, dating, married, etc.) Usually more Xs means more familiarity. Xs can be seen used between two people of the same sex without being regarded as homosexual.
2) Heard you were back in town sexy. Haven't had a good shag in ages, so how bout it? xxxxxx
3) Can you pick up some curry for dinner on your way home love? Cheers x
X can also mean but is not limited to the following:
2) The Roman numeral for Ten (10)
3) A variable, often seen in mathematics disciplines
4) A slang term for the drug MDMA also known as ecstasy.
5) A "kiss" when used at the end of a letter or other correspondence.
2. "To Romans, XXX = 30. To Americans XXX is usually accompanied by LIVE NUDES!"
3. "When the teacher tells me to solve for x I tell her to suck a d"
4. "When I'm rolling on x I always want to rub all over everything like a cat"
5. ...the end. xxxx OR sincerely, name xoxoxo