A newton is the amount of force required to accelerate 1 kilogram of mass at a rate of 1 meter per second, according to Dictionary.com. In the International System of Units, the newton is abbreviated "N".
The exact value of the newton was determined in 1946; however, it didn't receive its name until two years later. The newton is named in honor of Sir Isaac Newton, whose second law of motion provided the framework for understanding acceleration and the application of force that the unit was devised to measure. According to Wikipedia, tolerances for both tension and shear are often expressed in kilonewtons.