What is meant by the term edge set when referring to plywood planks used for boat sides?

Bill

Edge set is the bending of the wood plank in the direction towards either
edge.

Edge set is something that you can not get with plywood unless it is in very
narrow strips.

Wood planks in carvel planked hulls are sometimes edge set several inches in
the length of the plank.. However, in some very traditional planking, the
plank may be sawn to shape from a very wide plank. This sawing to shape is
used to great advantage in plywood planking.
--
My opinion and experience. FWIW

Steve
s/v Good Intentions