* Constellations are indeed groups of stars. But they're not just any group.
* They appear close together in the sky from our perspective on Earth. This is due to our line of sight, not because the stars are actually physically close to each other.
* Constellations have been given names. These names often come from mythology, history, or even the shapes the stars seem to form.
* They divide the sky into sections, but these sections are not "definite" in a scientific sense. Different cultures have different constellations, and the boundaries between them are somewhat arbitrary.
In short, constellations are patterns of stars in the sky that have been named and used to divide the sky into sections for cultural and historical purposes.
