Inflection refers to the modification of a word to express different grammatical categories such as tense, mood, voice, aspect, person, number, gender, and case. In linguistics, it involves changing the form of a word, like adding suffixes or prefixes, to convey various meanings or relationships in a sentence. For example, "talk" can be inflected to "talks," "talked," or "talking" to indicate different tenses or subjects. Inflection plays a crucial role in understanding the structure and meaning of sentences in many languages.