Simile. One can be found when Sheriff Tate tells Aunt Alexandra not to worry: "... if we followed our feelings all the time we'd be like cats chasing our tails."
Metaphor. Example: "Cecil Jacobs is a big fat hen."
Consonance. This alliterative device can be found in the repeated "t" and "c" sounds in "Atticus's instinctive courtesy failed him."
Antagonist. Bob Ewell is proved to be the antagonist of the assault on the children.
Idiom. Idioms are found when Scout tells the sheriff that "Jem yelled... loud enough to wake the dead"; and when Atticus tells Heck that most of the neighbors "go to bed with the chickens."
Catharsis. Scout experiences this form of emotional cleansing when she suddenly recognizes that the man standing in the shadows of the room is actually Boo Radley, and "our neighbor's image blurred with my sudden tears."
Foreshadowing. Scout's retelling of the attack by Bob Ewell foreshadows the fact that the unknown "somebody" who rescued Jem is actually Boo Radley.
Denouement. The entire chapter serves as part of the "unraveling of the main dramatic complications" of the attack on the children.