What does the mad dog that Atticus kills mean?
The mad dog Atticus faces down on the street has several meanings. The first one is that it shows a side of Atticus Scout had not known. It reveals her father's hidden depths, and implies a number of adventures she had not known about. The second one is that it shows his character. This rabid dog is a genuine threat to the town, and to his children, and Atticus stands up to it. He acts even though everyone is scared. That's important in itself. However, it also carries a third, more symbolic meaning. This mad dog symbolizes the mad rage of racism to which Atticus stands up to protect Tom Robinson. Just as he faced the mad dog without flinching, so Atticus will stand up to the fear, anger, and resentment of the entire community around him.