"Chain bookstores" refers to large retail stores that are part of a company with multiple locations. These stores have the same name and offer a wide variety of books and sometimes other items like magazines and stationary. Full definition
The majority of their purchases take place in chain bookstores (28 %) or online (25 %), with minimal purchases taking place in traditional bookstores (6 %). (booknetcanada.ca)
Good luck if your objective is to have your book in a major chain bookstore. (thebookshepherd.com)
Printed books, including retail shelving space, are disappearing at an alarming rate, as are big chain bookstores. (huffingtonpost.com)