There are two competing notions of the predicate in theories of grammar. 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. The second notion was derived from work in predicate calculus (predicate logic, first order logic) and is prominent in modern theories of syntax and grammar. In this approach, the predicate of a sentence mostly corresponds to the main verb and any auxiliaries that accompany the main verb; whereas the arguments of that predicate (e.g. the subject and object noun phrases) are outside the predicate. The competition between these two concepts has generated confusion concerning the use of the term predicate in theories of grammar. This article considers both of these notions.