duplex (adj.)youdaoicibaDictYouDict[duplex 词源字典]
1817, "composed of two parts," from Latin duplex, from duo "two" (see two) + -plex, from Greek plax (genitive plakos) "flat surface." The noun sense of "house for two families; two-story apartment" is American English, 1922.[duplex etymology, duplex origin, 英语词源]