whereabouts (adv.)youdaoicibaDictYouDict[whereabouts 词源字典]
"in what place," early 15c., from whereabout + adverbial genitive -s. The noun, "place where someone or something is," is recorded from 1795. Whereabout in this sense is from c. 1600.[whereabouts etymology, whereabouts origin, 英语词源]