tympanum

noun

1. 1

   A triangular space between the sides of a pediment.

2. 2

   The space within an arch, and above a lintel or a subordinate arch, spanning the opening below the arch.

3. 3

   The middle ear.

4. 4

   The eardrum.

5. 5

   A hearing organ in frogs, toads and some insects.

6. 6

   In certain birds, the labyrinth at the bottom of the windpipe.

7. 7

   A drum-shaped wheel with spirally curved partitions by which water is raised to the axis when the wheel revolves with the lower part of the circumference submerged; used for raising water, as for irrigation.