Gram*mat"ic*al (?), a. [L. grammaticus, grammaticalis; Gr. skilled in grammar, knowing one's letters, from a letter: cf. F. grammatical. See Grammar.]
1.
Of or pertaining to grammar; of the nature of grammar; as, a grammatical rule.
2.
According to the rules of grammar; grammatically correct; as, the sentence is not grammatical; the construction is not grammatical.
--Gram*mat"ic*al*ly, adv. -- Gram*mat"ic*al*ness, n.
© Webster 1913.