a house having separate apartments for two families, especially a two-story house having a complete apartment on each floor and two separate entrances.
From POTUS To FLOTUS: A Full (White) House Of AcronymsThe faster we move, the more abbreviations and assorted acronyms we use, and when it comes to talking about the folks who reside at 1600 Pennsylvania Avenue—otherwise known as the White House—there are plenty of acronyms to choose from.
Also called duplex.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for duplex house
US and Canadian a house divided into two separate dwellingsAlso called (US): semidetached
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012