Why is to kill a mockingbird titled to kill a mockingbird?

Answer 1

I read the other two answers and I don't remember anyone being killed in this book. It seems to me it is about a black man wrongly accused of rape who was freed by the justice system. It is also about a man, Boo Radley, who was misunderstood by the community because he was different, but he was really a good person.

These lines from Chapter 10 are the source of the novel’s title and introduce one of the key metaphors of the book: the idea of “mockingbirds” as good, innocent people who are destroyed by evil. Boo Radley, for instance, is like a mockingbird—just as mockingbirds do not harm people but only “sing their hearts out for us,” Boo does not harm anyone; instead, he leaves Jem and Scout presents, covers Scout with a blanket during the fire, and eventually saves the children from Bob Ewell. Despite the pureness of his heart, however, Boo has been damaged by an abusive father. The connection between songbirds and innocents is made explicitly several times in the book: in Chapter 25, Mr. Underwood likens Tom Robinson’s death to “the senseless slaughter of songbirds by hunters and children”; in Chapter 30, Scout tells Atticus that hurting Boo Radley would be “sort of like shootin’ a mockingbird.” The moral imperative to protect the vulnerable governs Atticus’s decision to take Tom’s case, just as it leads Jem to protect the roly-poly bug from Scout’s hand.

Answer 2

because a mockingbird is described as being something pure, which "does no harm and only gives music". and tom robinson represents the mockingbird, and he is killed, so it is titled to kill a mockingbird

Answer 3

A Mockingbird is supposed to be a harmless creature and to kill one would be a sin. Just like the Black man in the story (Tom? it's been a few years since I read it), was harmless and didn't commit the crime. To kill him was a sin.