Account—A book retailer (e.g. Amazon, Barnes & Noble, Costco, &c). While "store" can mean "account" or refer to an individual store (e.g. the Borders on Park Avenue in New York City), "account" always means "group of all stores with a given name." Roughly synonymous with "company."
Buyer—A person who works for a given account and is charged with buying books (or a select subdivision of books, e.g. science fiction, biographies, &c) from publishers for the account.
Co-op—Advertising/promotional space in book stores (front-of-store tables, in-section face-outs, endcaps, &c) that the publisher pays the account for, often on a monthly basis.
Hardcover—Also called "hardback" or "cloth," a book with a rigid cover (generally cardboard covered in cloth). Comes with a fancy dust jacket and a price in the $20.00 - $40.00 range (USD).
Mass market—Also called "paperback" or "rack-size," these are the "pocket-sized," extra-thick paperbacks printed on lower quality paper and at a smaller trim size. The price is generally in the $4.00 - $8.00 range (USD). Rather than being returned or remaindered, mass market editions are often stripped (see below).
Nielsen BookScan—A service provided by the Nielsen Company since 2001 that tracks book sales. It is estimated that BookScan captures about 70% of total sales, as not all retailers report to BookScan.
Remainder—Remaindered books are books that are no longer selling in sufficient quantities and are being liquidated by the publisher (i.e. sold to a third party at significantly reduced, often near-unit, cost). Oftentimes authors are given the option of buying their remaindered stock at unit cost before the title is offered up to other parties.
Returns—Often expressed as a percentage, returns are the books sent back to the publisher by the account(s). The return rate is described by (# of books returned by the account)/(# of books shipped to the account).
Sales call—A meeting during which a publisher's rep(s) meet(s) with an account's buyer(s) to sell books to the account.
Sales rep—A person employed in the sales division of a publishing house whose job it is to sell books to an account or accounts.
Sell-through—Also often expressed as a percentage, sell-through is the number of books sold by an account compared to how many it bought. It is described by (# of books sold by the account)/(# of books shipped to the account).
Stripped book—A book without a cover, almost always a mass market edition. Because it is not cost-effective to return or remainder mass market editions, their covers are torn off by the retailer and shipped back to the publisher as proof the books have been destroyed. The retailer then destroys the books. This is the reason for the "If you purchased this book without a cover..." note on the first pages of many mass market editions. Strippable books are marked with an "S" inside a triangle, often on the inside of the front cover.
Trade paperback—Also called "quality paperback," this is a paperback edition of a book with a trim size roughly comparable to the hardcover edition (if there was one) and larger than that of a mass market edition. The price range is generally $10.00 - $20.00 (USD).
Trim size—The dimensions of a book (generally in inches).