credentials (n.)youdaoicibaDictYouDict[credentials 词源字典]
"letters entitling the bearer to certain credit or confidence," 1670s, from Medieval Latin credentialis, from credentia (see credence). Probably immediately as a shortening of letters credential (1520s, with French word order); earlier was letter of credence (mid-14c.).[credentials etymology, credentials origin, 英语词源]