ウラシマ効こう果かalso: うらしまこうかウラシマこうかMeanings1nounUrashima effect; time dilationslang›Slang term for the phenomenon where time passes differently for someone traveling at high speed or in a different frame of reference, named after the Japanese legend of Urashima Tarō. Used in science fiction and popular science contexts.宇う宙ちゅう旅りょ行こうから帰