
Using slang acronyms became popular in the 1990s when internet chat rooms, message boards, and instant messaging rose to popularity.

The acronyms LMAO and LMBO probably stem from the original and still-trending internet slang term LOL, which stands for “laughing out loud.” LMAO and LMBO are considered stronger than LOL, and were likely invented in order to show when someone thought something was extremely funny. If someone was texting a parent or grandparent that did not approve of using curse words, one might opt to use the acronym LMBO over LMAO. Since LMBO is less vulgar than LMAO, people tend to use this in contexts where being very clean is important.

According to Urban Dictionary and 7 E S L, the acronym LMBO stands for “laughing my butt off.” This is a variation on the popular social media slang term acronym LMAO, which stands for “Laughing My A**” off.
