Ok, yeah that's a very different thing. I know that the dempsey step is different - wasn't sure about the other. But I'm thinking of something entirely different. I do know that type of 'footwork' just never thought of it as a distinct thing.No, not really the same thing. The drop or falling-step can be done moving forward a foot or more, or virtually standing in place. Here's an interesting video on it by Keith P. Myers who was once a very active, if somewhat cantankerous member of our forum. The first half is more about Dempsey's drop-step, then he get's off on the Bruce Lee/JKD footwork used to cover more ground:
Now, here is how Latosa dropped his weight striking ...in this instance with a stick. The video cuts off his feet, but you can see the torque and weight drop pretty clearly. Also, notice that he barely moves forward at all in this demo. This video was made back in the early 90s: