Ordnance Survey
/ˌɔːdnəns ˈsɜːveɪ/
/ˌɔːrdnəns ˈsɜːrveɪ/
(abbreviation OS)
- the British government organization responsible for making maps of Britain. These are available in a range of different scales, some of which are very detailed. They are especially popular with people who enjoy walking in the countryside. The OS was started in 1791 to make maps for the army. It also produces historical maps.