Meta is a word for which, like many other things, we have to thank the ancient Greeks. When they used it, meta meant behind, after, or behind. “Beyond” meta is still present in words like metaphysics or meta-economics. But this is still not the meta that most of us face today.
One of the most popular uses of meta today is the value that is best described by the formula “meta-X equals X over X”. So if we take the word “data” for our X and add a meta-prefix to it, we get metadata, or “data about data.” Meta-text is text about texts, metacognition is thinking about thinking, and meta-joke is a joke about jokes. The self-reflective sense of meta has also led to the use of the word as a standalone adjective, where meta is used to describe something that is self-reflective or self-referential.
A self-referential sense of meta seems to be especially popular in art. In its simplest form, a book in which a character writes a book or a movie in which a character makes a movie can be described as meta. Some works are more meta than others – for example, Birdman is a film about an actor who played a superhero in a film and is now trying to resume his theater career, and this actor is played by an actor who actually played a superhero in a movie and is now trying resume his career in a film that looks more like a play than a movie.
When characters in a work of fiction act as if they are aware that they are in a work of fiction, this technique is called meta-reference. It is often used in meta-fiction, a work of fiction in which the author breaks convention to show that the work is in fact fiction.
In the gaming world, meta is used in two ways. Meta can be used as an abbreviation for “most effective tactics available,” and calling something “meta” means that it is an effective way to achieve the goal of the game, whether it be to beat other players or beat the game itself. Meta can also be short for metagame, which uses information about the game from the world outside the game or its rules to influence the outcome of the game or gain a competitive advantage.