keirinEnglishOxford New American Dictionarykeirin /ˈkirin, , ˈkɪrɪn, kāˈrin, keɪˈrɪn / ▸ noun Cycling a racing event in which cyclists ride several laps around an indoor track behind a motorized pacesetter before sprinting to the finish. – ORIGIN 1950s : Japanese, literally ‘bicycle race’.