The acronyms "lol," "lmao," and "rofl" are all used to indicate laughter in online communication. Here are their meanings:

• lol: Laughing out loud.
• lmao: Laughing my ass off.
• rofl: Rolling on the floor laughing.

These acronyms are part of a larger set of internet slang terms and acronyms that have developed over time. Some of these terms are more widely used than others, and new terms continue to be created as online communication evolves.