Petřín is a hill in the centre of Prague, which is 327 metres high. On its top there is the Petřín Lookout Tower and many other buildings. “Petra” means “stone” in Latin, which is where the name Petřín was derived from. Stone – marlstone – was mined there for ages and was used for many constructions in Prague including the first churches in Prague Castle or the first bridge over the Vltava River. Petřín mines were first mentioned by Sázava Monk, who wrote that Abbot Silvester used Petřín stones to have the Sázava monastery church paved. In the course of centuries Petřín had several names: Petřín, the Mountain, the Hill, Saint Lawrence Hill, which name was derived from the patron saint of the church, who you can find on its hillside. Chronicler Kosmas described Petřín as a very rocky place.
A minor planet Petřínpragensis, which was discovered by Petr Pravec in Ondřejov in 1997, was named after Petřín. It could not be named simply Petřín, because it might be easily confused with already existing minor planet Petrina discovered in 1902. The applicable rules do not accept that.