At a high level the definition of grammar is a system of rules that allow us to structure sentences It includes several aspects of the English language like part of speech verbs adjectives nouns adverbs prepositions conjunctions modifiers etc clauses e g independent dependent and compound punctuation like commas semicolons and periods when applied to usage Mechanics of language like word order semantics and sentence structure At a high level, the definition of grammar is a system of rules that allow us to structure sentences. It includes several aspects of the English language, like: part of speech (verbs, adjectives, nouns, adverbs, prepositions, conjunctions, modifiers, etc.); clauses (e.g. independent, dependent, and compound); punctuation (like commas, semicolons, and periods, ...when applied to usage). Mechanics of language (like word order, semantics, and sentence structure)