A duplex is a 2-family home located on a single lot (parcel) and owned by one owner. Each residence has its own separate entrance. On the West Coast, a duplex is usually 2 houses side-by-side which are attached with a common wall. But in the Midwest, a duplex refers to a house with a residence on the main floor and a separate residence upstairs. A "duplexes" is also known as a “two-family house”. And a "flat" can refer to a residence within a multi-unit house.
A triplex has the same characteristics as a duplex, except that it consists of 3 units. It may also be referred to as a “three-family dwelling”. A fourplex, also known as a quadplex or quadruplex, is a 4-unit building, also owned by 1 person but rented out to 4 separate families.
Most first home buyers will not be shopping for a multi-unit residence because the values are higher than a single family home, or because many duplexes/triplexes/quadruplexes are older homes in more dense neighborhoods.
And any building which has 5 or more units is typically considered commercial property; in other words, an apartment complex. These properties do not offer residential financing as they are designed for investors, not for owner-occupied home owners.
Read more in our book, "Buy Your First Home", http://tinyurl.com/dy2wjx4.
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