"His" is a possessive pronoun used to indicate ownership or association with a male individual. It is commonly used in sentences to show that something belongs to or is related to a male person, such as in the phrase "his book" or "his car." In English grammar, "his" functions as a determiner and can also be used as a pronoun. For example, in the sentence "This is his," it replaces a noun to refer to something owned by the male subject. It is an essential part of the English language, helping to clarify relationships and ownership.