Matrix

Matrix usually refers to the 1999 science fiction film in which humanity unknowingly lives inside a simulated reality controlled by machines.

The film's central premise—that perceived reality might be an elaborate illusion—has become cultural shorthand for questioning appearances: Take the red pill and see how deep the rabbit hole goes.

References to the Matrix or being trapped in the matrix suggest artificial constraints on perception or thought.

The franchise spawned sequels and influenced philosophy, fashion, and action cinematography. (Lowercase matrix is a surrounding structure or mathematical array.)