JambThe vertical side or edge of a doorway, window, or other opening.
Source: Water Management Guide
Jump DuctA flexible, short, U-shaped duct (typically 10-inch diameter) that connects a room to a common space as a pressure balancing mechanism. Jump ducts serve the same function as transfer grilles. Used when return ducts are not located in every room.
Source: Info-604: Transfer Ducts and Grilles;(...)
