Hey kiddo, have you ever tried pushing something, like when you push your toy car or your book on the table? That kind of pushing is called a force. And when we talk about pounds of force, we mean how strong the force is.
So let's say you wanted to measure how hard you're pushing your toy car. If you have a scale that measures things in pounds, you can put the car on the scale and push against it. The scale will show how many pounds of force you're using to push the car.
Now, pound (force) is a unit that's used to measure force. It's the force required to accelerate a 1-pound mass at a rate of 32.174 feet per second squared. That may sound like a bunch of big words, but it means that if you were to push a 1-pound object and cause it to speed up by 32.174 feet per second in one second, you would be using 1 pound of force.
So, when someone says "I applied 10 pounds of force to lift the box," they mean that they used the same amount of force as it would take to accelerate a 10-pound object by 32.174 feet per second in one second.
I hope that helps you understand what pound (force) means!