What is the definition of roof slope or roof pitch?

The slope of your roof (or the roof pitch) is listed as rise over run. For example, a roof pitch listed as 4/12 would indicate the roof goes up 4 inches vertically for every 12 inches horizontally. 

The slope of your roof (or the roof pitch) is listed as rise over run. For example, a roof pitch listed as 4/12 would indicate the roof goes up 4 inches vertically for every 12 inches horizontally.