Roof

A roof is the top surface of the building.^[1] The plural of 'roof' is 'roofs'.^[1] The roof keeps out rain and snow and protects people from the sun. Some roofs are sloped, or pitched, so the rain and snow fall off easily. Some roofs are flat, but even flat roofs have a little bit of pitch so the water can flow away towards a drain.

1. ↑ ^{1.0 1.1} "roof". Merriam-Webster Dictionary. Merriam-Webster, Incorporated. Retrieved January 16, 2017.