Merriam-Webster Collegiate Dictionary - grammar

 noun  Etymology: Middle English gramere, from Anglo-French gramaire, modification of Latin grammatica, from Greek grammatike, from feminine of grammatikos of letters, from grammat-, gramma — more at gram  Date: 14th century  1.  a. the study of the classes of words, their inflections, and their functions and relations in the sentence  b. a study of what is to be preferred and what avoided in inflection and syntax  2.  a. the characteristic system of inflections and syntax of a language  b. a system of rules that defines the grammatical structure of a language  3.  a. a ~ textbook  b. speech or writing evaluated according to its conformity to grammatical rules  4. the principles or rules of an art, science, or technique a ~ of the theater; also a set of such principles or rules  • ~ian noun