LOL

LOL, an abbreviation for laughing out loud, or laugh out loud, is a common element of Internet slang. It was used historically on Usenet but is now widespread in other forms of computer-mediated communication, and even face-to-face communication. It is one of many initialisms for expressing bodily reactions, in particular laughter, as text, including initialisms for more emphatic expressions of laughter such as LMAO("laugh(ing) my ass off"), and ROTFL or ROFL ("roll(ing) on the floor laughing"). Other unrelated expansions include the now mostly historical "lots of luck" or "lots of love" used in letter-writing.
The list of acronyms "grows by the month" and they are collected along with emoticons and smileys into folk dictionaries that are circulated informally amongst users of Usenet, IRC, and other forms of (textual) computer-mediated communication. These initialisms are controversial, and several authors recommend against their use, either in general or in specific contexts such as business communications.
LOL was first documented in the Oxford English Dictionary in March 2011.