Wiktionary
alt. 1 (context uncountable English) The proportion of wholesale items that are eventually sold at retail 2 (context uncountable English) The practice of retailing items (such as DVDs) that are normally, or were previously rented 3 An item that is sold at retail (as opposed, for example, to being rented out). n. 1 (context uncountable English) The proportion of wholesale items that are eventually sold at retail 2 (context uncountable English) The practice of retailing items (such as DVDs) that are normally, or were previously rented 3 An item that is sold at retail (as opposed, for example, to being rented out).
Wikipedia
In publishing, sell-through refers to a percentage of units shipped which are actually sold. In the case of books, the rest is returned to the publisher. Other items, such as software, are usually discounted.
Sell-through is always expressed as a percentage. Net sales essentially refers to the same thing, in absolute numbers.
Sell through refers to sales made directly (Direct sales). Sell in, on the other hand, refers to sales made through a channel.
Usage examples of "sell-through".
The other DNA magazines all registered slight drops in circulation, although no disastrous plunges, and the sell-through for most of them was high as well.