Grammatical categories are classes or groups of words that share common characteristics and functions within a language's structure. They are sets of linguistic elements (e.g., nouns, verbs, adjectives) or features (e.g., tense, number, case) that organize how words and sentences are formed and interpreted. These categories help define the roles words play in sentences and how they relate to one another syntactically and semantically. Grammatical categories form the backbone of linguistic structure, providing the framework through which language conveys meaning, relationships, and context. These categories are essential for constructing coherent and grammatically correct sentences, enabling effective communication.