noun. 
                    A systematic account of the usages of a language, as regards especially the parts of speech it distinguishes, the forms and uses of inflected words, and the combinations of words into sentences; hence, also, a similar account of a group of languages, or of all languages or language in general, so far as these admit a common treatment.
                  
                
                  
                    noun. 
                    Grammatical statements viewed as the rules of a language to which speakers or writers must conform; propriety of linguistic usage; accepted or correct mode of speech or writing.
                  
                
                  
                    noun. 
                    A treatise on grammar.
                  
                
                  
                    noun. 
                    An account of the elements of any branch of knowledge, prepared for teaching or learning: an outline or sketch of the principles of a subject: as, a grammar of geography; a grammar of art.
                  
                
                  
                    noun. 
                    The formal principles of any science; a system of rules to be observed in the putting together of any kind of elements.
                  
                
                  
                    
                    To discourse according to the rules of grammar.