Counterweight (noun)

1. A weight used to balance another weight.
2. A force or influence that balances or offsets another.

Origin:

Derived from the combination of 'counter' meaning 'opposite' and 'weight' meaning 'a force that pulls objects towards the center of the earth.'.

Examples:

1. A counterweight is used in many types of cranes to balance the weight of the load being lifted.
2. The counterweight on a seesaw allows people on either end to balance each other.
3. The new regulations are seen as a counterweight to the growing power of corporations in the economy.
4. The counterweight system in the elevator kept the car from falling in case of cable failure.
5. In politics, the counterweight to the executive branch is the legislative branch, which can check and balance its power.