But what does it mean?

Cooper was running up and down the hall, throwing the ball to the dog. On his last run, he tripped and hit his head on our bed frame. He started crying, and immediately got a goose egg on his forehead. After a few minutes, when he could talk again, this is what he told us about his experience:

"I ran down to Hayden's door, then I was running back to your room and I had this (his new toy) in this hand, and I was running and I fell, and fell means that I tripped. And tripped means that I hit my head on your bed." And then he continued crying. It was all we could do to hold in our laughter until he ran off a few minutes later saying, "I have to go show all the kids my forehead." And of course he needed an otter pop to make it all better.