A shaft coupling is a mechanical component that connects the driveshaft and driven shaft of a motor, etc., in order to transmit power. Shaft couplings introduce mechanical flexibility, providing tolerance for shaft misalignment. The former is called a coupling and the latter is called a shaft coupling. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.