A cowbell is a metal bell that farmers attach to a cow's neck. It makes a loud noise when the cow moves, helping to keep track of them. Full definition
No need for more cowbell and cheering as a player is seizing on the ice. (diehardsport.com)
The only sound was bells; an unhurried melody chimed out from some church in the valley below and, closer to hand, the tinkling of cowbells as the locals grazed. (theexpeditioner.com)
Helicopters hovered loudly overhead while hundreds of police officers erected barricades, and protesters rang cowbells, blew whistles, waved signs, and sounded air horns. (nymag.com)