pepperbox

Etymology

pepper + box

noun

1. A pepper shaker.
2. (firearms) A repeating firearm with three or more barrels grouped around a central axis.
3. A buttress at one side of the court in the game of fives.
4. (architecture) A tower capped by a cupola, looking similar to a giant pepper shaker.
   Large, stately, and dark was its [the château's] outline against the dusky night-sky; there were pepper-boxes and tourelles and what-not fantastically going up into the dim starlight. 1861, Elizabeth Gaskell, The Grey Woman
5. (architecture, slang, chiefly in the plural) Any of the buildings of the Royal Academy and National Gallery in Trafalgar Square, London, having cupolas on the roof.
   I also remember the old Royal Mews that stood on the site of the present trumpery National Gallery, with its too suggestive pepper-boxes; […] 1887, Charles Mackay, Through the Long Day: Or, Memorials of a Literary Life, page 113
   Its architect, Wilkins, had the misfortune to be chosen to erect our much-abused National Gallery building, with its condemned "pepper-boxes" of cupolas; […] 2012, Edward Verrall Lucas, Highways and Byways in London