The term 'Sound of Thunder' is often used to describe the loud, booming sound that accompanies a thunderstorm. The crossword solutions for this term are BOOM (4 letters), PEAL (4 letters), and CLAP (4 letters). BOOM is a deep, low sound, usually associated with an explosion or a large object falling. PEAL is a series of loud ringing sounds, often heard in a sequence. CLAP is a sharp, sudden sound, usually made by two objects coming together quickly. All three words accurately describe the sound of thunder, making them suitable solutions for the crossword.