τύμπανον

Greek tympanon named a kettledrum — a drum made by stretching an animal skin (membrane) over a circular frame. The word comes from typtein (to strike). Both the architectural tympanum and the anatomical tympanic membrane (eardrum) were named by analogy to the drum's stretched membrane. The triangular stone field above a door is stretched between its frame like a drumhead.

The architectural tympanum is the semicircular or triangular space enclosed within the arch above a doorway and above the horizontal lintel below. In Romanesque and Gothic churches, the tympanum was the most prominent surface for sculptural decoration — the position directly above the main entrance. The Last Judgment scenes at Autun Cathedral (Gislebertus, c. 1130), Chartres Cathedral, and Notre Dame de Paris all fill the tympanum with monumental sculpture visible to every entering worshipper.

The tympanum's strategic position was deliberate: every person entering the church passed beneath the scene of judgment. The theological program was architectural — the message of salvation and damnation was placed where it would be unavoidable. Gislebertus signed his Autun tympanum with 'Gislebertus hoc fecit' (Gislebertus made this) — one of the earliest named attributions in medieval art.

The eardrum and the cathedral doorway share the name because both were understood as surfaces that received impressions from outside and transmitted them within. The drum membrane vibrates with the air's message; the tympanum sculpture receives the worshipper's gaze and transmits the theological message inward. The architectural term is an ancient anatomical metaphor applied to stone.