mi) is agricultural. The open areas within the built-up zone amount to 22 km (8.5 sq mi).
The city of Oslo was established as a municipality on 3 January 1838 (see formannskapsdistrikt). It was separated from the county of Akershus to become a county of its own in 1842. The rural municipality of Aker was merged with Oslo on 1 January 1948 (and simultaneously transferred from Akershus county to Oslo county). Furthermore, Oslo shares several important functions with Akershus county. The neighbouring industrial commune of Aker was incorporated into Oslo in 1948. the population after that went down fast at about 531,124.
The origin of the name Oslo has been the subject of much debate. It is certainly derived from Old Norse and was�in all probability�originally the name of a large farm at Bj�rvika, but the meaning of that name is disputed. Modern linguists generally interpret the original �slo or �slo as either "Meadow at the Foot of a Hill" or "Meadow Consecrated to theGods", with both considered equally likely.
Erroneously, it was once assumed that "Oslo" meant "the mouth of the Lo river", a supposed previous name for the river Alna. However, not only has no evidence been found of a river "Lo" predating the work where Peder Clauss�n Friis first proposed this etymology, but the very name is ungrammatical in Norwegian: the correct form would have been Loaros (cf. Nidaros). The name Lo is now believed to be a back-formation arrived at by Friis in support of his spurious etymology for Oslo.
Oslo is one of very few cities in Norway, besides Bergen and T�nsberg, that does not have a formal coat of arms, but which uses a city seal instead. The seal of Oslo shows the city's patron saint, St. Hallvard, with his attributes, the millstone and arrows, with a naked woman at his feet. He is seated on a throne with lion decorations, which at the time was also commonly used by the Norwegian Kings
