(intransitive) To leave a room or building with the expectation of returning soon. / (computing, intransitive) To appear on the screen as a temporary window or menu.

Third-person singular simple present indicative form of pop out

present participle of pop out

simple past tense and past participle of pop out

A construction in parties and celebrations which appears to be (and often partially consists of) a large cake, but which really conceals a person inside who will jump out to surprise the partygoers