underground — Public Transport underground /ˈʌndəɡraʊnd/ noun CEFR A2 A railway system that runs in tunnels below a city. “We travelled around London on the underground.” Related words in this scene luggagesuitcasepassengerseatdelayqueuetrainstationplatformtickettimetablecarriageconductordriverarriveleavewaitjourneychangemapaislebustaxistoptramsubwayfarerouteridetransferrush hour Practice this word Create worksheet