noun

1. that part of the study of language which deals with the forms and structure of words (morphology), with their customary arrangement in phrases and sentences (syntax), and now often with language sounds (phonology) and word meanings (semantics)
2. the system of a given language at a given time
3. a body of rules imposed on a given language for speaking and writing it, based on the study of its grammar (sense ) or on some adaptation of another, esp. Latin, grammar
4. a book or treatise on grammar
5. one's manner of speaking or writing as judged by prescriptive grammatical rules his grammar was poor
6. 1. the elementary principles of a field of knowledge
   2. a book or treatise on these

Etymology: ME gramer < OFr gramaire < L grammatica (ars, art) < Gr grammatikē (technē, art), grammar, learning < gramma, something written (see gram): in L & Gr a term for the whole apparatus of literary study: in the medieval period, specif., “the study of Latin,” hence “all learning as recorded in Latin” (cf. grammar school in Brit usage), and “the occult sciences as assoc. with this learning”: see gramarye, glamour