cupola

noun

Etymology: Borrowed from Italian cupola, from Latin cūpula (“little tub”); from Latin cūpa, cuppa (“cup”); named for its resemblance to a cup turned over. Doublet of cupula.

1. A dome-shaped ornamental structure located on top of a larger roof or dome.

   “the light falling dimly through the foggy cupola.”

   “The stations on the City & South London were small but pretty, with cupolas to accommodate the winding gear of the small and claustrophobic hydraulic lifts.”

2. A small turret, usually on a hatch of an armoured fighting vehicle.
3. An upward-projecting mass of plutonic rock extending from a larger batholith.
4. A solid formed by joining two polygons, one (the base) with twice as many edges as the other, by an alternating band of isosceles triangles and rectangles.
5. A type of furnace used for smelting.

   “The cupola has a small cylindrical chimney-like bore that is lined with a refractory material.”

   “Cast iron produced in a cupola possesses the following advantages : The cost of melting is low. The control of chemical composition is better. Temperature control is easier. Molten metals can be tapped from the cupola at regular intervals.”

6. A small cap over a structure that is shaped like a dome or inverted cup.

   “the posterior cupola of the cartilaginous nasal capsule”

   “From each anterior cupola there projects forwards the processus prenasalis lateralis inferior.”

7. a small viewing window in the top of the caboose for looking over the train, or the part of the caboose where one looks through this window.
8. A body of members of the Sicilian Mafia who make decisions and settle disputes.