The newton (N) is the SI base unit of force, defined as the force needed to accelerate one kilogram of mass at one meter per second squared. Named after Isaac Newton, it is the fundamental unit in mechanics, structural engineering, and physics worldwide. One newton equals approximately 0.2248 pound-force.

The dyne (dyn) is a centimeter-gram-second (CGS) unit of force equal to exactly 0.00001 newtons, used primarily in physics for small-scale force calculations. It represents the force needed to accelerate one gram of mass at one centimeter per second squared, and appears in surface tension and electromagnetic force measurements. One dyne equals exactly 10 micro-newtons.