LOL (also written with some or all letters lowercase) is a common element of Internet slang used historically on Usenet but now widespread in other forms of computer-mediated communication, and even face-to-face communication. It is an abbreviation for "laughing out loud"[1][2] or "laugh out loud".[3] LOL is one of many initialisms for expressing bodily reactions, in particular laughter, as text, including initialisms such as ROTFL ("roll(ing) on the floor laughing"),[4][5][6][7] a more emphatic expression of laughter, and BWL ("bursting with laughter"), above which there is "no greater compliment" according to technology columnist Larry Magid.[8] Other unrelated expansions include the now mostly historical "lots of luck" or "lots of love" used in letter-writing.[9]

...

总结：laugh out loud