A paradox, you see, is a thing that defies the logic of mere mortals. It's a concept that contradicts itself, like the answer to the ultimate question of life, the universe, and everything: 42, but only on Tuesdays, when the sun is shining, and the stars are in alignment.
And, of course, the mother of all paradoxes: The Paradox of the Self-Contradictory Paradox