Wikipedia
An Agraharam or Agrahara is the name given to the Brahmin quarter of a heterogenous village or to any village inhabited by Brahmins. Agraharams were also known as Chaturvedimangalams in ancient times. They were also known as ghatoka, and boya.
The name originates from the fact that the agraharams have lines of houses on either side of the road and the temple to the village god at the centre, thus resembling a garland around the temple. According to the traditional Hindu practice of architecture and town-planning, an agraharam is held to be two rows of houses running north-south on either side of a road at one end of which would be a temple to Shiva and at the other end, a temple to Vishnu. An example is Vadiveeswaram in Tamil Nadu.
With Brahmins taking up professions in urban areas and some migrating abroad agraharams are vanishing fast. Many of the traditional houses are giving way to concrete structures and commercial buildings.