Almost every large moon in the solar system orbits over its planet's equator. Ours does not: it stays within about five degrees of Earth's path around the Sun instead.

A moon that formed from a disc around its planet inherits the planet's equator, which is what Jupiter's and Saturn's big moons do. Ours is tied to the Sun's plane, which is one of the strongest hints that it did not form quietly in orbit but was thrown together after a collision, far enough out that the Sun's pull mattered more than Earth's bulge.