A counterweight is a heavy object used to balance or offset the weight of something else. It is used to keep things stable and prevent them from tipping over. Full definition
Kettlebells debuted in 18th - century Russia, where they were used as counterweights to measure grain and other dry goods. (onnit.com)
As you'd expect with heavy pistons stroking a full four inches and not a hint of counterweight on the spindly crankshaft, all Model Ts shake like North Pole sunbathers. (automobilemag.com)
The state acted as liberator of an oppressed humanity; its power, concentration, and extent increased as a necessary counterweight for the control of non-state institutions. (firstthings.com)