- a borough in SE London, England: located on the prime meridian from which geographic longitude is measured; formerly the site of the Royal Greenwich Observatory.
- a town in SW Connecticut.
- Greenwich Time.
- a Greater London borough on the Thames: site of a Royal Naval College (now used as the National Maritime Museum), including Inigo Jones’ Queen’s House (1617), and of the original Royal Observatory designed by Christopher Wren (1675), accepted internationally as the prime meridian of longitude since 1884, and the basis of Greenwich Mean Time; also site of the Millennium Dome. Pop: 223 700 (2003 est). Area: 46 sq km (18 sq miles)
