(1):

(n.) A chamber in the anterior part of the syrinx of birds.

(2):

(n.) One of the naked, inflatable air sacs on the neck of the prairie chicken and other species of grouse.

(3):

(n.) The recessed face of a pediment within the frame made by the upper and lower cornices, being usually a triangular space or table.

(4):

(n.) 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.

(5):

(n.) The ear drum, or middle ear. Sometimes applied incorrectly to the tympanic membrane. See Ear.

(6):

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