Cantilever
In it’s strictest terms, this is simply a physical element that’s only connected to a large structure at one end, so the other end “hangs out in space.”
Architecturally, a cantilever is a building structure that protrudes into open space, such as a balcony.
A great example is The Guthrie Theater and its observation deck which hangs out over the Minnesota River.
Why I Looked It Up
I posted to the Dull Men’s Club group on Facebook about some flagpoles. See the image above:
The text was this:
While my wife was shopping, I noticed with interest that these flagpoles are not simply affixed to the facade. Rather, they are fully cantilevered through the parapet.
Some people commented that “this isn’t a cantilever,” so I looked it up.
I disagree – it’s a cantilever even if it’s supported in the middle. It doesn’t matter where in the span that the support is located; it only matters that one end of the span is supported and the other is not.
However, someone else said something like, “This would be a cantilever even if the flags were affixed to the facade,” and this is correct. So I was right in one sense, but wrong in another.