Silly Question, but property relevant: Is a duplex the same as..

[Brad Taylor]

Hey all, just some property terms that seem a bit unfamiliar.  Here in Chicago, I never hear anyone talk about a “duplex, triplex, or fourplex”.  Are these always considered separate units on the same lot?  In Chicago, most buildings are vertical “2-flat, 3-flat, or 4-flat”, but they are all in the same building.  Typical city apartment living.  Could anyone clarify the terms as well as the relationship between the buildings and the land, if relevant?

[Brie Schmidt]

@Brad Taylor - In Chicago we use the word "flat" to define how many units.  The term duplex is used to define how many floors one unit occupies.  

So you could be looking at a 3 flat with a duplex down.  That means the basement and first floor are 1 unit.  The second floor is 1 unit and the third floor is 1 unit.  So 3 units but 4 floors of living space.  It is a Chicago thing.  Everywhere else this would be called a triplex

Duplex down means the entrance is on the first floor and additional living space is on the floor below.  Duplex up is the opposite with additional living space above.