One kilonewton is 224.8089431 pounds-force. This is the conversion that lets a European structural or safety rating be read against an American one, and the scale is where climbing gear, lifting equipment and engine thrust all live.
About the units
The kilonewton is a thousand newtons, the SI force unit at structural scale. The pound-force is the gravitational force on one pound of mass at standard gravity, exactly 4.4482216152605 N. Neither is more correct; they simply belong to different documentation traditions. Safety equipment is where the pair matters most to non-engineers, because the ratings are life-critical and the two markets label identical products differently.
The exact factor
The exact value is 1,000 ÷ 4.4482216152605 = 224.808943099711 lbf per kN. Reference points from safety equipment: a climbing carabiner rated 24 kN holds 5,395 lbf; a standard climbing rope withstands about 15 kN of impact force; and a lifting sling rated 2 tonnes is about 19.6 kN or 4,409 lbf. In aerospace, a jet engine producing 100 kN of thrust is producing 22,481 pounds of thrust — and American sources will state the second figure, often abbreviated to 22,500 lbf.
Where you meet this conversion
Climbing, rigging and lifting equipment, where European gear is marked in kilonewtons and American in pounds. Rocket and jet thrust figures, which are quoted in kilonewtons by European manufacturers and pounds-force by American ones, so comparing engines requires the conversion before any conclusion. Structural connection capacities, anchor bolt ratings and crash test forces all cross the same boundary in international projects.