a house with two units sharing a common wall
"They decided to buy a duplex, living in one unit while renting out the other to generate extra income."
an apartment having rooms on two floors that are connected by a staircase
"They bought a duplex where they take the stairs to get from their kitchen on the ground floor to their bedroom upstairs."
A house made up of two dwelling units.
"The real estate agent showed us their new duplex, which features separate entrances and kitchens on each floor."
In plain English: A duplex is an apartment building that contains exactly two separate living units, usually stacked on top of each other or side by side.
"They bought an affordable duplex to live in with their brother and sister-in-law."
change into a duplex
"The large house will soon be converted into a duplex to accommodate two separate families."
To make duplex.
"The technician decided to duplex the cable before connecting it to the main server."
allowing communication in opposite directions simultaneously
"duplex system"
"duplex telephony"
Double, made up of two parts.
"The duplex apartment was divided into two separate living spaces connected by an internal staircase."
In plain English: Duplex means something that has two parts, such as an apartment building with two separate living spaces on each floor.
"We moved into their new duplex apartment because we needed more space than our studio could offer."
The word duplex comes from Latin and originally meant "two-fold" or double. It was formed by combining the root for two with a verb meaning to fold together before entering English usage.