The Collaborative International Dictionary of English v.0.48:

Nuraghe \Nu*ra"ghe\, n.; It. pl. -ghi. Also Nuragh \Nu"ragh\,
   etc.[It. dial. (Sardinia) nuraghe).]
   One of the prehistoric towerlike structures found in
   Sardinia.

         The so-called nuraghi, conical monuments with truncated
         summits, 30-60 ft. in height, 35-100 ft. in diameter at
         the base, constructed sometimes of hewn, and sometimes
         of unhewn blocks of stone without mortar. They are
         situated either on isolated eminences or on the slopes
         of the mountains, seldom on the plains, and usually
         occur in groups. They generally contain two (in some
         rare instances three) conically vaulted chambers, one
         above the other, and a spiral staircase constructed in
         the thick walls ascends to the upper stories.
                                                  --Baedeker.
   [Webster 1913 Suppl.]