Image for use in basic articles dealing with parse trees, nodes, branches, X-Bar theory, linguistic theory. S for sentence, the top-level structure in this example.NP for noun phrase. The first (leftmost) NP, a single noun "John", serves as the subject of the sentence. The second one is the object of the sentence.VP for verb phrase, which serves as the predicate.V for verb. In this case, it's a transitive verb hit.D for determiner, in this instance the definite article "the".