Martello

 
Pronunciation: /mɑːˈtɛləʊ/
(also Martello tower)

noun (plural Martellos)

  • any of numerous small circular forts that were erected for defence purposes along the coasts of Britain during the Napoleonic Wars.

Origin:

alteration (by association with Italian martello 'hammer') of Cape Mortella in Corsica, where such a tower proved difficult for the English to capture in 1794