往返票(wǎng fǎn piào) - return ticket, round-trip ticket in Mandarin

往返票 (wǎngfǎnpiào) is a return ticket. 往 (wǎng) means "towards, to go", 返 (fǎn) means "to return, to come back", and 票 (piào) is ticket, so the compound covers both directions of a journey in one word.

It is standard travel-booking vocabulary alongside 单程票 (dānchéngpiào, single ticket), and comes up constantly at train, bus and airport counters and on booking apps.

返 (fǎn) is worth noting on its own: it appears in other "return, back" words too, such as 返回 (fǎnhuí, to return, to go back), so recognising it here makes those easier to guess later.