pop-up /ˈpɒpʌp/adjective 4noun 4pop up verb 4forms 4 adjective4 •Coming into view suddenly from a concealed position.I packed a pop-up hamper in my suitcase. •Operating or existing for a brief period only; temporary. •Opening out to form a three-dimensional structure when the page of a book is opened.[…] I had a pop-up book of sexual organs by the time I was four –[…] — 1985 •Employing the cold launch technique. noun4 •(Internet) A pop-up advertisement; an advertisement that is triggered to appear on a computer screen when the user accesses a particular web page. •A business that opens for a brief temporary period only, such as a temporary restaurant.I came across this recipe when Helen Graham cooked it for Bracia and Friends, a pop-up whose USP is that chefs must cook a single dish. — 2024 •A folded paper element which pops up from a book, greeting card, etc. •A pop-up ball: a ball that has been hit to a considerable height above the infield or the shallow outfield; a pop fly. pop up verb4 •To come up with a "pop" sound.The toast is in the toaster - when it pops up it will be ready. •(Of an alert, advertisement, etc.) To suddenly appear onscreen.And then up popped on my screen something truly bizarre. •To display as an alert, advertisement, etc. that suddenly appears on screen.My computer just popped up a warning about Internet security. •(informal) To appear without warning.I can't remember where I left my keys, but they normally pop up somewhere. formspopped up · popping up · pops up · pop-ups