If Your Referencing To the book:"When he gave us our air-rifles Atticus wouldn't teach us to shoot. Uncle Jack instructed us in the rudiments thereof; he said Atticus wasn't interested in guns. Atticus said to Jem, "I'd rather you shot at tin cans in the back yard, but I know you'll go after birds. Shoot all the bluejays you want, if you can hit 'em, but remember it's a sin to kill a mockingbird." That was the only time I ever hear Atticus say it was a sin to do something, and I asked Miss Maudie about it. "You're father's right," she said. "Mockingbirds don't do one thing but make music for us to enjoy. They don't eat up people's gardens, don't nest in corncribs, they don't do one thing but sing their hearts out for us. That's why it's a sin to kill a mocking bird." (98)I think the best definition of 'a mockingbird is said by Atticus in this quote"I'd rather you shot at tin cans in the back yard, but I know you'll go after birds. Shoot all the bluejays you want, if you can hit 'em, but remember it's a sin to kill a mockingbird."Followed up by "Mockingbirds don't do one thing but make music for us to enjoy. They don't eat up people's gardens, don't nest in corncribs, they don't do one thing but sing their hearts out for us. That's why it's a sin to kill a mocking bird."