In The Outsiders, a ‘heater’ is a slang term for a gun. Dally, one of the characters in the novel, carries a heater because he is deeply involved in the gang lifestyle and often finds himself in dangerous situations. The gun serves as a means of protection and a symbol of his tough, rebellious nature.
Dally’s possession of a heater also reflects his readiness to resort to violence when necessary. Throughout the story, Dally is portrayed as someone who has little regard for the law and is willing to take extreme measures to protect himself and his friends. This characteristic makes him a complex and somewhat tragic figure in the novel.