/ ˈdjuːpleks; NAmE ˈduː-/ noun ( especially NAmE )
1.
a building divided into two separate homes
2.
a flat / apartment with rooms on two floors
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WORD ORIGIN
mid 16th cent. (as an adjective): from Latin duplex, duplic- , from duo two + plicare to fold. The noun dates from the 1920s.