A giant is a humanoid creature who is far larger than humans.
In Xanth Edit
Giants in Xanth are invisible and usually naked. They were once humans who wanted to be larger, so they asked a magician to help them. In return they built the magician a mountain. At first they were embarrassed by being naked, though because of their size, they did not get cold. Also their size makes them invisible to smaller creatures. Most male giants do not smell very good, making them easier to detect.