"The way words are put together to make units of meaning
A system of rules that in some explicit and well-defined way assigns structural descriptions to sentences
The underlying structure of a language that any native speaker of that language knows intuitively
The principles or rules of an art, science, or technique
The study of the classes of words, their inflections, and their functions and relations in the sentence
A set of actual or presumed prescriptive notions about correct use of a language
Something that’s best learned through writing . . ."
(List of definitions of "grammar")