A textbook describing the rules of grammar of a language.
A precise description of a formal language.
The classification, and the system or set of structural rules that governs the composition, gestalt, and form of sentences, phrases, and words in any given natural or artificial human language. General and descriptive linguistics are researching and documenting them.
studies of the formation of basic linguistic units
the branch of linguistics that deals with syntax and morphology (and sometimes also deals with semantics)