A box office hit is a movie or other form of entertainment that has been extremely successful in terms of ticket sales and revenue. The term can be broken down into three crossword solutions: SMASH (5 letters), SELLOUT (7 letters), and LINE (4 letters). SMASH is an informal term used to describe something that is very popular and successful, while SELLOUT refers to the fact that tickets for the movie or event have sold out quickly. Finally, LINE is a reference to the long lines of people waiting to purchase tickets for the box office hit.