Declension is a grammatical term that refers to the way nouns, pronouns, and adjectives change form to express different grammatical categories such as case, number, and gender. For example, in languages like Latin or German, a noun can have different endings depending on whether it is the subject, object, or showing possession. This helps clarify the role of the word in a sentence. In English, declension is less prominent, but we still see it in pronouns. For instance, the pronoun he changes to him when used as an object. Understanding declension helps learners grasp how words interact within sentences, enhancing their language skills.