There are a few conjectures as to what the D  stands for. Some have said it is an abbreviation for departure  or decision.  Others claim that it stands for doomsday.  However, according to the United States military, the origin of the popular nickname has more to do with their terminology.

To scoop someone is to get the news story before they do. Officially it means, a piece of news published by a newspaper or broadcast by a television or radio station before its rivals.  People use it in many ways nowadays, including to mean that they have the latest gossip, or got something before everyone else.

scooped up; scooping up; scoops up. informal. : to take or buy (something) in a quick and eager way.