Declensions in Czech grammar are an essential aspect of the language. They refer to the inflection of nouns, adjectives, pronouns, and numerals in order to indicate their grammatical function in a sentence. Czech declension system is quite complex, with seven cases (nominative, genitive, dative, accusative, vocative, locative, and instrumental) and various declension patterns depending on gender and ending. Mastering Czech declensions is crucial for understanding and constructing sentences in the language.