Толковый словарь английского языка Oxford English Reference - grammatical

adj. 1 a of or relating to grammar. b determined by grammar, esp. by form or inflection (grammatical gender). 2 conforming to the rules of grammar, or to the formal principles of an art, science, etc. Derivatives grammatically adv. grammaticalness n. Etymology: F grammatical or LL grammaticalis f. L grammaticus f. Gk grammatikos (as GRAMMAR)