trade paperback : Often used to indicate any paperback book that is somewhat larger than a mass-market paperback.

reprint : Any printing of a book which follows the original edition. By definition, a reprint is not a first edition.

first thus : Indicates that this is not the first appearance of a book in print, but that this is the first appearance in a substantially different format than the true first edition. For example, a first illustrated edition of a book, or even a first paperback release of a book originally published in hard cover.