Need help on a few terms

[wdwfan]

I need help figuring out a few terms when it comes to vintage cards. I don't deal in graded, but I've thought about starting it. So I've been looking at graded cards, and I'm seeing some with initials I'm not familiar with. I see graded cards all the time, and I'll see MK. Does that mean miscut? I'm guessing so. What about ST?

I'll also see something marked in the price guide as a DP. Now I know SP is short print, but what does DP mean? Does that mean double player? Like 2 or 3 players on one card?

Final question. I notice how a bunch of the higher #d cards in a set go for more. Are the higher series cards distributed differently to make them more valuable? Or are there fewer of them than the regular set run that makes them more expensive?

For instance, I'm working on a 1962T set. I have about 330 different. Only about a dozen of those are high #s. Were those high #s short printed? Or only distributed in a certain region? Or what makes them so much more valuable.