A "bestseller" refers to a book or other product that sells a significant number of copies, often ranking high on sales lists. These lists can be compiled by various organizations, such as The New York Times or Amazon, and typically reflect sales over a specific period. Bestsellers can span various genres, including fiction, non-fiction, and self-help. The term is often associated with popular authors like J.K. Rowling or Stephen King, whose works frequently achieve bestseller status. Achieving this label can significantly boost an author's visibility and sales, leading to increased readership and potential adaptations into other media, such as films or television series.