Force meter
A force meter is an instrument to measure the magnitude of a force. This is often just a spring contained within a cylinder that has a scale to mark the extension of the spring produced by the force. In the International System of Units, the unit of force is the newton (symbol N). A force meter that measures force in newtons may be referred to as a newtonmeter.
Gc (engineering)
In unit systems where force is a derived unit, like in SI units, "g" is equal to 1 and is not needed. In unit systems where force is a primary unit, like in English units, "g" is not equal to 1, and is required to obtain correct results.