Here's why:

* Our solar system: All the planets in our solar system orbit around one star, which we call the Sun.

* Stars are suns: The word "sun" is simply the name we give to our own star. Other stars in the universe can also be called "suns."

* Other solar systems: There are many other solar systems in the universe, each with its own star (sun) at the center. Planets in those systems orbit their own star.

So, while each planet in a solar system orbits a sun, it's not like each planet has its own individual sun.