Universals are concepts or properties that apply to multiple instances or entities across different contexts. For example, the idea of color can be seen in various objects, such as apples, skies, and cars, all of which can possess colors like red, blue, or green. Universals help us categorize and understand the world by identifying common traits shared by different things. In philosophy, the debate about universals often centers on whether they exist independently of the objects they describe. This discussion includes perspectives like realism, which argues that universals exist as abstract entities, and nominalism, which claims that universals are merely names or labels we use to group similar objects.