Predicate

There are two competing notions of the predicate, generating confusion concerning the use of the term predicate in general. The first concerns traditional grammar, which tends to view a predicate as one of two main parts of a sentence, the other part being the subject. The purpose of the predicate is to complete an idea about the subject, such as what it does or what it is like. For instance, in a sentence such as Frank likes cake, the subject is Frank and the predicate is likes cake.

The second notion of predicates is derived from work in predicate calculus (predicate logic, first order logic) and is prominent in modern theories of syntax and grammar. The predicate is a semantic unit that takes one or more arguments and relates these arguments to each other. On this approach, the predicate in the example sentence Frank likes cake is the verb likes, and the nouns Frank and cake are its arguments. Both of these predicate concepts are considered in this article.