Well, to come back to the topic, Drop D or Dropped D is taking _only_ the bass string down. That seems to have been established above, and is certainly the case. Years ago Joe Hickerson came up with this (as close as I recall):

Folksingers, proud and young, when you run your E string down,
Don't go down to funky D, it'll make you sing off key.

To the tune of Gordon Bok's Bay of Fundy, of course singing the last note flat.