They both have the same meaning but the former is used in the UK and the latter in the USA. Anyhoo, here’s one of my favourite mini sheets sent to me several years ago from the beautiful city of Talinn.
Issued by Eesti Post in 27 March 2006, the mini sheet features stamps with perforations running to the edge of the sheet. Featured are the drawings of the Estonia theatre and concert building (Armas Lindgren and Wivi Lönn) and what could possibly be the present-day Estonia’s National Opera in the centre, costume designs for Evald Aav’s opera Vikerlased (Vikings) on the left with its musical notes providing the background of the mini sheet, and on the right is Estonian ballerina Helmi Puur in Tchaicovsky’s Swan Lake.Estonia’s National Opera was opened in 1906, first as a professional theatre called Estonia, founded by the directors and actors Paul Pinna and Theodor Altermann. Initially offering mainly drama, the theatre gradually opened its doors to musical productions. The Estonia theatre and concert building was completed in 1913 but was destroyed in an air raid by the Soviets in 1944. It was later reopened in 1947 after the war and, in 1998, was renamed the Estonian National Opera. (Source) The ceiling was painted in the style of Socialist Realism. Now, I’m curious to see what that looks like.