[Date: 1300-1400; Language: Old French; Origin: gramaire, from Latin grammatica, from Greek grammatikos 'of letters', from gramma; ⇨ ↑gram]
1. [uncountable] the rules by which words change their forms and are combined into sentences, or the study or use of these rules:
Check your spelling and grammar.
the rules of English grammar
2. [countable] a particular description of grammar or a book that describes grammar rules:
A dictionary lists the words, a grammar states the rules.