The newton (symbol: N) is the SI (International System of Units) derived unit of force. It is defined as 1 kilogram·meter/second2.
Pound force :
The pound-force (symbol: lbf) is a unit of force used in the English Engineering System and the British Gravitational System.
It is defined as the gravitational force exerted on a mass of one avoirdupois pound under the condition of standard gravity (9.80665 m/s2). Under this definition, with mass in terms of slugs, one pound-force is equal to 1 slug·foot/second2.