pop-up pop-up /ˈpɒpˌʌp/

noun

1. (baseball) a short high fly ball  ( pop-fly , pop-up , pop fly )
   (baseball) a short high fly ball
   
2. A book (usually for children) that contains one or more pages such that a three-dimensional structure rises up when a page is opened  ( pop-up , pop-up book )
   a book (usually for children) that contains one or more pages such that a three-dimensional structure rises up when a page is opened