A web page, often containing advertisements, that appears unexpectedly when a user is browsing.
Internet
A box that literally pops up when a browser views a page that the window is linked to. Pop-ups are normally used for advertising or as a medium for a form that has to be filled in by a user in order to proceed.
Geology and Earth Sciences
The relatively uplifted section of a hanging wall which is formed by back thrusting. The structure is bounded by the back thrust and by the major thrust from which the back thrust originated.