-bar (x) is a system of grammatical analysis developed in recent generative linguistics as an alternative to traditional account of phrase structure grammar. It is argued both that rules of phrase structure grammar need to be more constrained and that more phrasal categories need to be recognized. Within the noun phrase, for example, the need is felt to recognize intermediate categories larger than the noun but smaller than the phrase, e. g. very fast or very fast car in the noun phrase the very fast car. The intermediate categories, which have not status in previous phrase structure models, are formally recognized in x-bar syntax by a system of x-bars, each of which identifies a level of phrasal expansion. Given a lexical category, X, X5 = X withe no bars (i.e. the category itself; x = X1 = X bar = X singular bar; X = X2 = X double bar; Z = X3 = X treble bar and so on, Expansion for N (N bar and N double bar) can be illustrated in the following tree.