- an apartment with rooms on two connected floors.
Origin of duplex apartment
An Americanism dating back to 1935–40
Also called duplex.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- US and Canadian an apartment on two floors
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