Related Clues:

• Source of a thundering sound
• War tactic
• Crowd
• Cattle that all have the same brand
• Crusades tactic
• Military assault
• Moving stock
• Wartime tactic
• Round up
• Driven animal group
• Stampede group, maybe
• Savanna group
• Bison bunch
• Drover's group
• Long, drawn-out attack