[1] : The Collaborative International Dictionary of English v.0.48

martello tower \martel"lo tow`er\ 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. 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.
   1913 webster

   note: the english borrowed the name of the tower from corsica
         in 1794.
         1913 webster
see also:
martel 

[2] : WordNet (r) 2.0

martello tower
     n : a circular masonry fort for coastal defence

Martello Tower >> M Words
Martello Tower, definition of term: Martello Tower
martello+tower_pag1.html

Tower >> T Words
Tower, definition of term: Tower
tower_pag1.html

Water Tower >> W Words
Water Tower, definition of term: Water Tower
water+tower_pag1.html

Conning Tower >> C Words
Conning Tower, definition of term: Conning Tower
conning+tower_pag1.html

Bell Tower >> B Words
Bell Tower, definition of term: Bell Tower
bell+tower_pag1.html

Ivory Tower >> I Words
Ivory Tower, definition of term: Ivory Tower
ivory+tower_pag1.html

Control Tower >> C Words
Control Tower, definition of term: Control Tower
control+tower_pag1.html

Tower Of Babel >> T Words
Tower Of Babel, definition of term: Tower Of Babel
tower+of+babel_pag1.html

Tower Of London >> T Words
Tower Of London, definition of term: Tower Of London
tower+of+london_pag1.html