D defs.my
Entry 1 sense Webster, 1913

Martello tower

/mär-tĕl'-ō tou'-ẽr/ · Mar·tel·lo tow·er · IPA
01 A building of masonry, generally circular, usually erected on the seacoast, with a gun on the summit mounted on a traversing platform, so a…
  1. 1.
    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.(Fort.)