According to nominalism, how do universals exist?

Nominalism posits that universals, such as properties or qualities shared by different entities, do not exist as real entities in the external world but rather as ideas or concepts that exist only in name. Under this framework, universals are not considered to have an independent existence outside of the specific instances that we encounter in reality. For example, the concept of "redness" does not exist as a tangible entity; instead, it is a term we use to describe a common characteristic shared by various red objects. By identifying universals as mere names or labels, nominalism emphasizes the subjective and linguistic nature of how we conceptualize similarities among different things. This viewpoint contrasts with realism, which asserts that universals have a concrete, independent existence.