I thought it was the other way around. (A "drone" is--or was, I guess, since it can be anything now, even a barge--an unmanned aircraft used for target practice

I thought it was the other way around. (A "drone" is--or was, I guess, since it can be anything now, even a barge--an unmanned aircraft used for target practice, so all drones are UAVs.) Guess that goes to show how confused the terminology is. Guess we'll just have to deal with the word meaning nothing, like "cloud". It did have a particular meaning, but then the term got extended to other military UAVs when they started using them for other missions, due, I guess, to lack of a better term. ("UAV" is a mouthful.) And then to autonomous quadcopters as a civilian version of a UAV. And now, apparently, to any small helicopter thing or any autonomous robot vehicle. Soon, it'll probably mean any robot. However, I guess the SpaceX "autonomous spaceport drone ship" is a bit more accurate to the original meaning than usual. It's mission in life does seem to be target practice.