pop up

Verb

pop up (third-person singular simple present pops up, present participle popping up, simple past and past participle popped up)

1. (intransitive) To come up with a "pop" sound.
   • The toast is in the toaster - when it pops up it will be ready.
2. (idiomatic, informal, intransitive) To appear without warning.
   • I can't remember where I left my keys, but they normally pop up somewhere.
   • Across Japan, technology companies and private investors are racing to install devices that until recently they had little interest in: solar panels. Massive solar parks are popping up as part of a rapid build-up that one developer likened to an "explosion."2013 June 21, Chico Harlan, “After Fukushima, Japan beginning to see the light in solar energy”, in The Guardian Weekly, volume 189, number 2, archived from the original on 25 Feb 2021, page 30
3. (intransitive) (Of an alert, advertisement, etc.) To suddenly appear onscreen.
   • And then up popped on my screen something truly bizarre.
   • […]where you should put the disclaimer for software (somewhere that the user sees it when they start the program, tho' I wouldn't do that, just put it in the 'about' box like the mpgn.com guy suggests -- otherwise, having something pop up makes it annoyware, IMHO).1994 September 8, Kendall Bullen, “COPYRIGHT POLICY”, in rec.games.frp (Usenet)
4. (transitive) To display as an alert, advertisement, etc. that suddenly appears on screen.
   • My computer just popped up a warning about Internet security.