martello tower Meaning, Definition & Usage

  1. noun a circular masonry fort for coastal defence

WordNet

Mar*tel"lo tow`er
Etymology
It. martello hammer. The name was orig. given to towers erected on the coasts of Sicily and Sardinia for protection against the pirates in the time of Charles the Fifth, which prob. orig. contained an alarm bell to be struck with a hammer. See Martel.
Definitions
  1. (Fort.) A building of masonry, generally circular, usually erected on the seacoast, with a gun on the summit mounted on a traversing platform, so as to be fired in any direction. ✍ The English borrowed the name of the tower from Corsica in 1794.

Webster 1913