Truth window

A truth window is like a secret peek-a-boo hole that people use to see what materials are inside the walls of a building. When a house or building is made, it's built with lots of different layers like a cake. Some of those layers include insulation, pipes, wires, and lots of other stuff that is hidden behind the walls.

A truth window is a small section of the wall that has been left open so that people can peek through and see what's inside. It's called a truth window because it allows people to see what's really inside the walls and to make sure that the builders used the right materials.

So, it's kind of like when we play hide and seek, and we're trying to find our friends by peeking through small holes or cracks. The truth window is the same idea, except instead of trying to find our friends, we're trying to see what's inside the walls of a home or building.