The term 'thunderous sound' is a combination of three words: PEAL, CLAP, and BOOM. A PEAL is a loud ringing sound, usually made by bells. A CLAP is the sound made when two objects are struck together, such as hands. A BOOM is a loud, deep sound, often associated with explosions or thunder. Together, these three words create a powerful and intimidating sound that is often associated with storms and other natural phenomena.