Definition of twin paradox in US English:

twin paradox


  • The apparent paradox arising from relativity theory that if one of a pair of twins makes a long journey at near the speed of light and then returns, he or she will have aged less than the twin who remains behind.

    • ‘As in the classical twin paradox, an observer at rest relative to the preferred inertial frame measures the longest proper time between any two events on his or her world line; moving observers always measure less.’
    • ‘This paradox, also called the clock paradox and the twin paradox, is an argument about time dilation that uses the theory of relativity to produce a contradiction.’
    • ‘When you return to your computer, via the twin paradox the computer will be much older than you, and will, hopefully have solved the problem.’
    • ‘So I'm sure she doesn't remember me, but I remember those papers on topology and also a paper she wrote with J.D. Barrow on the twin paradox in compact universes.’
    • ‘A crackpot attacked the twin paradox as ‘propaganda’ for the ‘orthodox’ view of relativity in a mailing to several scientists.’