In painting an attribute is an object (often symbolic) associated with - and seeming to identify - a particular figure, such as a saint.
For instance, Saint Peter holds the keys of Heaven and Hell and Saint Catherine leans upon the wheel to which she was bound in an attempt to kill her.
A saint's attribute is normally connected with his or her life in some way. Thus Mary Magdalene is often shown with a pot of ointment because she anointed Christ's feet, and Saint Peter Martyr with a cleaver in his head, one of the instruments of his martyrdom.
In altarpieces, painting the saints with their attributes helped to identify them.