Two supermassive black holes are locked in an orbital dance at the core of the distant galaxy OJ 287. This diagram shows their sizes relative to the solar system. The larger one, with about 18 billion times the mass of our sun (right), would encompass all the planets in the solar system with room to spare. The smaller one is about 150 million times the mass of our sun (left), which would be large enough to swallow up everything out to the asteroid belt, just inside the orbit of Jupiter.
Stars in other stellar systems are called stars. There’s only one star in the universe named the Sun, and its system is the only Solar System in the universe. The same is true for solar wind (vs. stellar wind), solar mass, solar day, solar radius, etc. — all of these terms refer to Sol, a.k.a. the Sun.