chaps (n.1)youdaoicibaDictYouDict[chaps 词源字典]
1844, American English, short for chaparejos, from Mexican Spanish chaparreras, overalls worn to protect from chaparro (see chaparral).[chaps etymology, chaps origin, 英语词源]
chaps (n.2)youdaoicibaDictYouDict
"jaws, cheeks," from chap (n.), 1550s, of unknown origin. Hence, chap-fallen (1590s).