The phrase "largest bookstore" refers to a bookshop that has the greatest size or the most extensive collection of books compared to other bookstores. Full definition
Large bookstore chains started to rule the inner cities and small book stores started dying since they lost their bread - and - butter business. (blog.literarily-starved.com)
If the book is good enough, commercial publishers can get your book into large bookstores. (americas-press.com)
If you're ordering from online retailers or large bookstores though, you should be good to go, buy and read! (kuriousity.ca)