interdome

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. The open space between the inner and outer shells of a dome or cupola of masonry.

from the GNU version of the Collaborative International Dictionary of English

• n. The open space between the inner and outer shells of a dome or cupola of masonry.

from The Century Dictionary and Cyclopedia

• n. In a masonry cupola, the space between the inner and outer shell; by extension, the space between the inner masonry cupola and the outer dome-like roof of wood or metal, as in St. Paul's Cathedral, London. Also called intercupola.