You want to know why The Matrix is called The Matrix? Well, it's because the movie centers around a computer simulated virtual world known as the Matrix in which humans are mentally trapped and placated so that they can be kept alive and produce energy.
Okay, maybe there's a bit more to it. What does "matrix" mean in the first place? If you just Googled it like we did, you probably found a bunch of definitions that don't really make sense within the context of the movie: "the thickened epithelium at the base of a fingernail or toenail from which new nail substance develops." Thanks Merriam Webster, but for some reason we don't think the movie has much to do with nail growth.
Ah, but wait. What about: "set of numbers arranged in rows and columns to form a rectangular array." Now we're getting somewhere. "Matrix" seems to refer to the structure and complexity of the system, whose underpinnings can be seen in the cascading green code of the operator computers and even more accurately when Neo is resurrected and begins to see the matrix itself in its true state.