I think they are pretty much all reprints, but I guess people who collect foreign books prefer the term "edition" when referring to the first book of a specific issue that was printed in that country, then the later reprints as just that, "reprints." In actuality, they are all reprints, but when you are collecting all the editions from all over the world, I guess it is easier to see a reprint of ASM 129 from 1976, more of an original then say one from 1999. Variants, to me, are those that are print the same book, in the US.