The name Elizabeth Alexandra Mary, the unique title The Queen of England, and the definite description the elder daughter of Cecilia Bowes Lyon all refer to the same unique entity. We might think of them as species of one kind of thing, as they have at least one feature in common: they refer (designate a single entity).
They are all nominals. However, nominals includes words that don't (at least not obviously) designate a single entity. For example, the word running in the sentence running is good for you. Is there a hypernym (general term) that designates all, and only, linguistic entities that refer?