Here are some examples:
* "The door had a large open for the dog to pass through." Here, "open" refers to the gap or space created by the door being open.
* "The hikers found an open in the trees that revealed a beautiful view." Here, "open" refers to a gap or break in the trees.
* "The store had an open in the wall that let in the sunlight." Here, "open" refers to a hole or gap in the wall.
In these cases, "open" functions as a noun, and it is not acting as an adjective describing something else.