Broch

A broch (pronunciation: /ˈbrɒx/) is an Iron Age drystone hollow-walled structure of a type found only in Scotland. Brochs belong to the classification "complex atlantic roundhouse" devised by Scottish archaeologists in the 1980s. Their origin is a matter of some controversy. The theory that they were defensive military structures (an Iron Age equivalent to the castles and tower houses of medieval Scotland) is not accepted by many modern archaeologists (see the 'general references' below), while the alternative notion that they were farmhouses is dismissed by some others. Although most stand alone in the landscape, some examples exist of brochs surrounded by clusters of smaller dwellings.

The word broch is derived from Lowland Scots 'brough', meaning (among other things) fort. In the mid-19th century Scottish antiquaries called brochs 'burgs', after Old Norse borg, with the same meaning. Place names in Scandinavian Scotland such as Burgawater and Burgan show that Old Norse borg is the older word used for these structures in the north. Brochs are often referred to as 'duns' in the west. Antiquaries began to use the spelling 'broch' in the 1870s.

A precise definition for the word has proved elusive. Brochs are the most spectacular of a complex class of roundhouse buildings found throughout Atlantic Scotland. The Shetland Amenity Trust lists about 120 sites in Shetland as candidate brochs, while the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) identifies a total of 571 candidate broch sites throughout the country. Researcher Euan MacKie has proposed a much smaller total for Scotland of 104.

...
Wikipedia