Ordnance Survey map
noun/ˌɔːdnəns ˈsɜːveɪ mæp/
/ˌɔːrdnəns ˈsɜːrveɪ mæp/
- a very detailed map of an area of Britain or Ireland, prepared by an organization called the Ordnance Survey, which is supported by the government
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Ordnance Survey map