WordWeb Online

1. 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 book
    
2. A short high fly ball
   - pop fly, pop-fly

1. Appear suddenly or unexpectedly
   "He suddenly popped up out of nowhere"
   - crop up, pop

Derived forms: popping up, pops up, pop-ups, popped up

Type of: appear, book, fly, fly ball

Encyclopedia: Pop up