a unit of cultural information, such as a cultural practice or idea, that is transmitted verbally or by repeated action from one mind to another

I just finished reading Fluke, a novel by Christopher Moore. Here is a paragraph from the book:

Nate knew about memes, the information equivalent of a gene. A gene existed to replicate itself and required a vehicle, an organism, in which to do it. It was the same with memes, except a meme could replicate itself across vehicles, across brains. A tune you couldn’t get out of your head, a recipe, a bad joke, the Mona Lisa—all were memes of sort. They were a fun model to think about, and computers had made the idea of a self-replicating piece of information more manifest with computer viruses, but what did that have to do with— But then it hit him. Why he’d learned about memes in the first place…