双ふた子ごのパラドックスMeanings1nountwin paradoxphysicsA thought experiment in special relativity where one twin travels at high speed and returns younger than the other.双ふた子ごのパラドックスは、特とく殊しゅ相そう対たい性せい理り論ろんの有ゆう名めいな思し考こう実じっ験けんです。The twin paradox is a famous thought experiment in special relativity.