From Longman Dictionary of Contemporary Englishthe tubethe tubeBritish EnglishTTT the system of trains that run under the ground in London SYN subway American Englishtake/catch the tube Take the tube to Acton. a tube stationby tube It’s best to travel by tube. → tube
Examples from the Corpus
the tube• Let's see what's on the tube tonight.the tubethe tubeAmerican English spokenTELEVISION/RADIO the television What’s on the tube tonight? → tube 