If you are egocentric, you look at the world as if it turns around you. You think first about what you want, how you feel, and how things touch you, and you do not really take in what other people might need or want. We use it of a person, and of a way of thinking. It is a fairly formal, slightly cold word — the kind a teacher, a doctor, or a psychology book might use. In everyday talk people more often say selfish, though that is not a perfect match: a selfish person may know other people matter and still choose themselves; an egocentric person may not even see the other person's side. Young children are often a bit egocentric in this second way: they are not being nasty; they have not yet learned that other minds are different. You will also hear it as a noun: “He is an egocentric,” meaning that kind of person.