A symbolic object that is conventionally used to identify a person or deity.  For example, the attributes of the Greek god Apollo are a lyre and bow; the attribute of the Hindu god Vishnu is a trident; the attribute of St. Catherine is the wheel on which she was martyred.

 St Catherine

St. Catherine. Detail from the Thornham Parva Retable. Painted oak and gilding. 1335-40. Church of St. Mary, Thornham Parva, Suffolk, England.