: of, relating to, or having a component or device that pops up
a pop-up book
2
: appearing suddenly: such as
a
computing: appearing suddenly on a screen over another window or display
a pop-up window
a pop-up ad
b
of a business: set up quickly for short-term operation in a temporary location
pop-up stores/shops
pop-up retail
The front lawn of nearly every home becomes either a parking lot or a pop-up market, perfect for hungry, thirsty fans held captive by the … lines of traffic. Juliet Macur
c
meteorology: appearing or developing quickly in isolation rather than as part of a line or grouping of storms
By Thursday you should be able to go coast to coast and see only pop-up thunderstorms … Paul Clark
Late summer is prime time for "pop-up" thunderstorms: storms born of hot, moist air that occur without regard to frontal activity or other large weather disturbances that are more easily understood.The Journal & Courier (Lafayette, Indiana)