An abbreviation of "laughing on the inside".
Nick: lol. not literally. silently really, but there is no abbreviation for that
Qyle: did you mean to say that to me
cause i have no idea what it means
Nicholas: I was comenting on my own "lol" It was honestly not out loud
laughing on the inside
check it out, i just blew ur mind w/ that revolutionary new internet slang