catch-up (n.)youdaoicibaDictYouDict[catch-up 词源字典]
"a working to overtake a leading rival," by 1971, probably a figurative use from U.S. football in reference to being behind in the score. From verbal phrase catch up, which was used from early 14c. in sense "raise aloft" and from 1855 in sense "overtake;" see catch (v.) + up (adv.).[catch-up etymology, catch-up origin, 英语词源]