In the context of gears, what does 'dedendum' refer to?

The term 'dedendum' specifically refers to the portion of a gear tooth that is located below the pitch circle, which is the circle that defines the size of the gear. This area is critical because it represents the part of the tooth that comes into contact with the mating gear's teeth during operation. Understanding this concept is crucial for comprehending gear design and functionality, particularly in ensuring that gears mesh properly and transmit power efficiently without excessive wear or failure.

In gear terms, the dedendum works together with the 'addendum,' which is the part of the tooth above the pitch circle. This distinction helps engineers and millwrights assess the dimensions of gear teeth for proper engagement and to calculate important aspects like the spacing between gears and the overall gear ratios.