- a grammar in which linguistic elements are categorized in terms of their ability to combine with one another to form larger constituents.
- a theory that characterizes syntactic categories in terms of functions between classes of expressions. The basic classes are names (N) and sentences (S). Intransitive verbs are symbols for functions which take a name and yield a sentence (written S/N), adverbs form compound verbs from verbs (for example, run fast) and so are (S/N)/(S/N), etc
