A traditional term for the study of the rules governing the way words are combined to form sentences in a language. In this use, syntax is opposed to morphology, the study of word structure. An alternative definition (avoiding the concept of ‘word’) is the study of the interrelationships between elements of sentence structure, and of the rules governing the arrangement of sentences in sequences. In this use, one might then talk of the ‘syntax of the word’. In initial formulations of generative linguistics, the syntactic component is one of three major organizational units within a grammar, containing rules for the generation of syntactic structures (e.g. phrase-structure rules, transformational rules). The exact nature of the syntactic rules within this component varies from one grammatical theory to another. Syntactic structures (patterns, or constructions) are analysable into sequences of syntactic categories or syntactic classes, these being established on the basis of the syntactic relationships linguistics items have with other items in a construction. Some studies propose an analysis whereby categories are analysed as sets of syntactic features, to permit a greater degree of generalization across categories. The study of the field as a whole is known as syntactic theory. Studying the sequential arrangements of syntax is sometimes referred to as syntactics, but there is a possibility of confusion here with the earlier used of this term as one of the three major divisions of semiotics (along with pragmatics and semantics). The adjective form of ‘syntax” in modern linguistics is syntactic.