Scout first asks Calpurnia what rape is in chapter 12. Calpurnia, a wise woman, advises Scout to ask her father about the definition. Scout gets her chance to ask Atticus what rape is in chapter 14. Atticus's philosophy about answering children's questions is to be direct and not try to skirt the issue. So, being a wise man, he gives his young daughter the legal definition of rape in an effort to answer her, but also to avoid any graphic illustrations of the subject. Atticus's definition is as follows:
". . . rape was the carnal knowledge of a female by force and without consent" (135).
Scout's reaction is a bit funny because she pretends to understand what that means, but she doesn't. She just asks Atticus why Calpurnia didn't answer her when she first asked about rape. Unfortunately, Atticus doesn't get a chance to elaborate on the legal definition of rape because Aunt Alexandra pitches a fit about Scout having been at Calpurnia's church when she asked about rape. Hence, there is no more discussion about the definition of rape, for which Atticus must be relieved. The reason that the legal definition proves to be such a success is because Atticus doesn't flinch at the question; he confidently answers his daughter, which leaves no room for her to doubt him or to think that he is trying to avoid the subject.
As always, Atticus Finch tells it like it is when Scout demands to know what rape means in Harper Lee's novel, To Kill a Mockingbird. When Scout initially asks her Uncle Jack "what a whore-lady was," he beats around the bush. When Scout questions Calpurnia about rape, she instructs her to ask her father. Since Scout knows she can talk with Atticus about anything, she does.
"What's rape?" I asked him that night.
Atticus looked around from behind his paper... He sighed, and said rape was carnal knowledge of a female by force and without consent.
Scout was less than enthused by Atticus' accurate definition, and drops the matter. But it only led to another argument between Atticus and Aunt Alexandra concerning Calpurnia's place in the Finch family.