From Longman Dictionary of Contemporary Englishtympanumtym‧pa‧num /ˈtɪmpənəm/ noun (plural tympanums or tympana /-nə/) [countable] technicalHBH an eardrum
Examples from the Corpus
tympanum• Walk around the outside of the N transept of the church whose fine tympanum relief is now in St George's Gallery.• The north doorway has a remarkable tympanum deeply set in the porch like that at Autun.• The tympanum is exceptionally large and, with the lintel below, depicts the Last Judgement. 