I think we’re using internet slang meme “short easily consumable joke primarily popularised on the internet”.

Using the OG definition I think broadly covers the lemmyverse as a whole.

This definition is for the meaning of meme in memetics, the study of ideas. This definition covers almost all concepts, including the concept of an internet meme, which also often contain the kind of meme he is describing here. Not really the same thing, even though this is where the name comes from.