Tympan

Part of speech: noun (n.)

1. A drum. [Obs.]

2. A panel; a tympanum.

3. A frame covered with parchment or cloth, on which the blank sheets are put, in order to be laid on the form to be impressed. Tympan sheet (Print.), a sheet of paper of the same size as that to be printed, pasted on the tympan, and serving as a guide in laying the sheets evenly for printing. W. Savage.