Does anyone else use the term "flat" in the US to refer to a unit of a duplex, where the duplex is by floor (1 unit upstairs, 1 unit downstairs) rather than side by side?

Posted by jaker9319@reddit | AskAnAmerican | View on Reddit | 616 comments

So famously in the US we use the term apartment whereas in the UK they use the term flat. But I actually do use the term flat for a very specific type of apartment unit (as described in the question). I live in the suburbs of Detroit, and have heard of people use the term here (which is how I learned it) but I also have met people in the Detroit area who didn't know of the term being used that way. So maybe it's also an older term that has slowly gotten out of use... But yeah, curious if the use of the word flat is used in this specific way by anyone else.