We refer to our star as the Sun. We live on one of nine planets which are accompanied by moons, comets, asteroids, gas and dust in a collection of stuff circling our star. We refer to this stuff and the Sun as our Solar System. The Sun is one star among 100 billion stars in the Milky Way, which is a flat disk-shaped spiral galaxy 100,000 lightyears in diameter with a bulge at the center, like a huge blazing pinwheel floating through space. A star is a sphere of hot glowing gas, a single ball of fire in space, often millions of miles in diameter.
Stars differ in size, brightness and color.
The material in some stars is 10,000 times as thin as Earth's air at sea level. On the other hand, some stars are so dense a cupful of material would weigh tons if it could be brought down to Earth. Inside, stars have temperatures measured in millions of degrees. At their surfaces, temperatures up to 55,000 degrees are common. Stars are a long way off, yet all stars visible from Earth, even with telescopes, are within our own Milky Way galaxy.