velocity (n.)youdaoicibaDictYouDict[velocity 词源字典]
early 15c., from Latin velocitatem (nominative velocitas) "swiftness, speed," from velox (genitive velocis) "swift, speedy, rapid, quick," of uncertain origin, perhaps related to vehere "carry" (see vehicle), or from the same root as vigil.[velocity etymology, velocity origin, 英语词源]