cupula

noun
cu·​pu·​la | \ ˈkyü-p(y)ə-lə How to pronounce cupula (audio) \
plural cupulae\ -​ˌlē How to pronounce cupulae (audio) \

Medical Definition of cupula

1 : the bony apex of the cochlea
2 : the peak of the pleural sac covering the apex of the lung