So, back to the original question about what MOD means. Well MOD is the ratio of the pitch circle diameter (PCD) to the number of teeth. DP for imperial gears is the number of teeth per one inch of pitch circle diameter. So whilst that may well answer the question, it doesn't really help appreciate the size of a gear.
doer. n. 1. a person or thing that does something or acts in a specified manner: a doer of good. 2. an active or energetic person. 3. a thriving animal, esp a horse. (Ëdu Ér). n.
United States Department of Energy. The United States Department of Energy (DOE) is a Cabinet-level department of the United States Government concerned with the United States' policies regarding energy and safety in handling nuclear material.