That's a great question! It's true that most moons are smaller than the planets they orbit, but it's not always the case. Here's why:

* Definition of a Moon: A moon is a natural satellite that orbits a planet.

* Definition of a Planet: A planet is a celestial body that orbits a star and is massive enough to be rounded by its own gravity.

The exceptions:

* Pluto and Charon: Pluto and its largest moon, Charon, are so close in size that they are sometimes considered a double planet system. Charon is about half the size of Pluto, which makes it significantly larger than many other moons.

* Earth's Moon: While Earth's moon is smaller than Earth, it's still the largest moon in the solar system relative to its planet.

So, the answer is not a simple yes or no:

* Most moons are smaller than their planets.

* There are exceptions, like Pluto and Charon, where the moon is a significant fraction of the planet's size.

It's all about the relative sizes and the specific definitions we use to categorize celestial bodies!