* The Great Tom: This is the largest bell in the church tower, a 16th-century masterpiece that has a special resonance and history. It's the bell that the murderer tries to use to their advantage.
* The Nine Tailors: This is actually a set of bells, but the term is sometimes used to refer to the entire peal of twelve bells in the church. It's a crucial element of the story because the number of bells, and the specific order in which they are rung, play a key role in the mystery.
While not named individually, the other bells in the set are also important. They are rung in different combinations, and their sounds provide clues to the murderer's identity and motives.