The term "sich" is a German reflexive pronoun that translates to "oneself" in English. It is used in sentences where the subject and the object are the same, indicating that the action is performed by the subject upon itself. For example, in the phrase "Er wäscht sich," meaning "He washes himself," "sich" reflects that the action of washing is directed back to the subject. In German grammar, "sich" is often used with reflexive verbs, which require the pronoun to convey the correct meaning. These verbs can express actions like "sich freuen" (to be happy) or "sich anziehen" (to get dressed). Understanding how to use "sich" is essential for mastering the nuances of the German language.