Lewis & Short

grammătĭcālis, e, adj. [grammatica], of or perlaining to grammar, grammatical: figurae, Sid. Ep. 7, 9: palaestra, id. Carm. 23, 212.
Adv.: grammătĭ-cālĭter, grammatically: declinare, Treb. XXX. Tyr. 10, § 5.