Ani (兄) means "my older brother." You use this term when referring to your own older brother while speaking to someone who is not part of your family. For addressing your older brother directly, or when talking about someone else's older brother, use "oniisan" (お兄さん). Example: 私の兄は大学生です。(Watashi no ani wa daigakusei desu.) = My older brother is a university student.

自分(じぶん)の兄(あに)を、家族(かぞく)以外(いがい)の人(ひと)に話(はな)す時(とき)に使(つか)います。例(れい)：私(わたし)の兄(あに)は大学生(だいがくせい)です。