I. ˌOrdnance ˈSurvey, the BrE AmE abbreviation , OS
an official organization which makes very detailed and correct maps of Britain and Ireland. The maps are used by people walking in the country, and each map has its own OS number. ⇨ compare ↑ US Geological Survey
II. OS /ˌəʊ ˈes/ BrE abbreviation for
1 . ↑ Ordnance Survey
2 . ↑ outsize