grammar

1. A system of rules and principles for speaking and writing a language.
2. The study of the internal structure of words (morphology) and the use of words in the construction of phrases and sentences (syntax).
3. A book describing the rules of grammar of a language.
4. A formal system specifying the syntax of a language.
5. Actual or presumed prescriptive notions about the correct use of a language.
6. A formal system defining a formal language
7. The basic rules or principles of a field of knowledge or a particular skill.
8. A textbook.

   a grammar of geography

9. A grammar school.

   2012, Graeme Paton, A green light for more grammars? (in The Daily Telegraph, 11 January 2012)

verb

To discourse according to the rules of grammar; to use grammar.