Coosh was a common food for Confederate soldiers, making use of their cornmeal rations; the Union soldiers received hardtack instead of cornmeal.
Etymology: The most common suggestion is that it's just a merger of 'cornmeal' and 'mush'.
couche-couche (or cush cush) is a similar dish, made with milk but no bacon, and traditionally served at breakfast with milk and sugar; sometimes the cornmeal is browned first.
If thick enough, coosh could be sliced and then fried in butter or bacon grease.
Coosh, cornmeal mush, and polenta are all very similar, and all can be allowed to thicken and set so they can be sliced and fried.
Where I grew up, fried cornmeal mush was the standard.
Some of these words or variations also have common but non-culinary slang meanings.