1610s, from French tube (15c.), from Latin tubus "tube, pipe," a word of unknown origin. The London subway was christened the Twopenny Tube by 1900 (H.D. Browne, in the "Londoner" of June 30); tube for "cylindrical railway tunnel" is attested from 1847. The meaning "TV as a medium" is from 1959, short for cathode ray tube or picture tube. Tube top as a women's clothing style is attested from 1972. Tube steak is attested from 1963 as "frankfurter," slang meaning "penis" is recorded by mid-1980s.