Slope:
Measured by rise in inches for each 12 inches of horizontal run: A roof with a 4-in-12 slope rises 4 inches for every foot of horizontal distance (also known as roof pitch).

Square:
The common measurement for roof area. One square is 100 square feet (10 by 10 feet).

Starter Course:
The first row of shingles applied to the base of your roof.