fartlek (n.)youdaoicibaDictYouDict[fartlek 词源字典]
1952, Swedish, from fart "speed" (cognate with Old Norse fara "to go, move;" see fare (v.)) + lek "play" (cognate with Old Norse leika "play;" see lark (v.)).[fartlek etymology, fartlek origin, 英语词源]