Pepperbox

Noun

1. A pepper shaker.
2. 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. A tower capped by a cupola, looking similar to a giant pepper shaker.
5. Any of the buildings of the Royal Academy and National Gallery in Trafalgar Square, London, having cupolas on the roof.