Meaning of Fermat's last theorem

Fer•mat's' last' the'orem

Pronunciation: (fer-mäz'), [key]
— Math. Math.
  1. the unproved theorem that the equation x + y = z has no solution for x, y, z nonzero integers when n is greater than 2.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.