Active:In paired or double doors, the hinged door leaf which is primarily operable.
Astragal:A wood or steel 'post' attached on the latch-side edge of one of a set of paired or double doors, which covers the space between doors when they are closed. Which acts like a stop for the active door.
Ball-Bearing Hinge:A heavier-duty hinge than the standard hinge, with bearings supporting the pivots. Ball-bearing hinges are usually used for heavy doors that will be in commercial or industrial use.
Ball Catch:A spring loaded ball mechanism that is inserted into the top edge of doors that have dummy locks. The ball engages a plate on the header that has a dimple to receive the ball, which in turn keeps the door closed.