In metaphysics, a Universalia is what particular things have in common, namely characteristics or qualities. In other words, Universalia are repeatable or recurrent entities that can be instantiated or exemplified by many particular things.
They are the universal ideas of everything that exists in the universe. They are the abstracts of our objects. There are multiple philosophies about these concepts, but the core question remains “Are we able to mentally conceive of these ideas?”. What is THE Universalia, where did they come from, and how can we think about them?