Single word or nounphrase that replaces a dependent clause is called

A pronoun stands in the place of a noun. Like nouns, pronouns can serve as the subject or object of a sentence: they are the things sentences are about. Pronouns include words like he, she, and I, but they also include words like this, that, which, who, anybody, and everyone ... This noun is called the antecedent.

A noun phrase

A noun phrase is either a pronoun or any group of words that can be replaced by a pronoun.