An ad that displays in a new browser window behind the current browser window.
The pop-under ad is the sneakier relative of the pop-up ad. While pop-up ads are often shown (and closed) instantly, pop-under ads linger behind the current browser window, appearing only after other windows have been closed.
see also: Digital Marketing Tools
beyond the banner, interstitial, pop-up ad
view all terms in the Online Advertising glossary or all terms in the Digital Marketing glossary