IPA: /ɡrəˈmætɪkəl/
KK: /grəˈmætɪkəl/
Relating to the rules and structure of a language, especially in terms of how words are combined to form sentences correctly.
The teacher explained the grammatical rules of the English language to the students.
Grammatical → It is formed from "gramma" (from Greek "γράμμα", meaning letter or something written) and "-ical" (meaning pertaining to). The word "grammatical" refers to something that pertains to letters or the rules of writing and language.
Think of 'letters' ('gramma') and remember that 'grammatical' means related to the rules of language and writing.