I love the Wikipedia definition - "A shack is a type of small house , usually in a state of disrepair."
Here are some local shacks I've been working on recently. I've been experimenting with a more stripped down, linear style of drawing.
You could call them sheds, huts or shanties as there are a lot of different names to describe the same kind of thing, but just now I like the word shack, even though these local buildings are not really what you could call a 'small house'.
I expect there are subtle differences within the taxonomy of dilapidated buildings - what makes a shed not a hut, for example. I'm too tired to think about this tonight as I've spent all weekend and the previous week completely rebuilding and reorganising my studio space. What was a messy shack-like area is now more of a super organised roofless shed within the larger studio space.