"In the ‘Iwata Asks’ interview he asked Masuda to explain why the games are called Pokémon X and Pokémon Y.
He replied, “The X and Y represent the x axis and the y axis,” and explained, “The world holds people with all sorts of ways of thinking, and you can get a sense that they exist in different dimensions. But if you think of them as people who think on the x axis and people who think on the y axis-horizontal and vertical axes-then they intersect somewhere.”
This reflects on the way both games make use of the Nintendo 3DS online functions, that see players from all over the world thrown against each other in battle. He added, “We may think differently, but we all live on the same planet, so everyone eats, sleeps and goes about their business day after day just like everyone else.”