D/D, D/Die, Double die, Doubled D, D doubled - I have a pet peeve! These and many other types of discriptions are being used on here and other sites to try and say, "doublED die". Now I know the whole world wants to "shorten up" the english language at every bend in the road. I also know that many people "who are new" don't know what the correct terms really are. But for those of us that do know we owe it to the collecting community here to use the right terms each time to avoid further confusion when we can. So here goes: A D/D is an RPM or Repunched Mintmark. A D/Die is nothing. A double die is nothing, it means nothing because it is incorrect. A doublED die is correct. A Doubled "D" is incorrect, we have the term RPM. Same goes for D/Doubled - it means nothing. Also I don't much like and don't think we should keep using MDD, PMDD. This area of the hobby is complicated enough without us that do know better adding to it's confusion. I mean, "are we going to get to the point that we say "FODSOOCE" or a "filp over double struck out of collar error" - if there even is such a thing - well, you get my point. If we know what we mean let's use the right phrases and wording to at least give the new people a chance at understanding what we mean instead of fogging thier minds with numbing, vague, indiscript 3 & 4 letter combinations?
This hobby as with all others, and virtually any other line of business has its own language. The abbreviations noted in the OP are all useful and used by most of us almost every day. But if we decide that CoinTalk will set the definations for numismatic abbreviations we should probably expect some dissent. For examble, RS Yeoman's famous Red Book, or should we call it A Guide Book of United States Coins (insert your favorite year here), freely uses D/S and D/D abbreviations to represent overmintmark's, see page 8 in your 2010 edition. I'm open to ideas as to how we would enforce our definations on the industry. Just being pratical, which isn't easy to do with your tongue in your cheek.
I have no problem with D/D being an RPM or D/S being an OMM. I have no problem with D/D being an RPM or D/S being an OMM. That is what I said - it's when we have to wonder about D/D meaning RPM or doublED die.
