* Primary Star: A primary star is the dominant star in a star system. It's the largest and brightest star, providing the majority of the system's light and gravity. Our Sun fits this definition perfectly.

* Secondary Star: A secondary star is a smaller, fainter star that orbits a primary star. They often exist in binary star systems, where two stars orbit around a common center of gravity.

The Sun is the only star in our solar system. It doesn't have a companion star, making it a primary star by definition.