Ur was a supercontinent that formed 3,000 million years ago (3 billion) in the early Archean eon; perhaps the oldest continent on Earth, half a billion years older than Arctica, but it may have been preceded by one other supercontinent, Vaalbara, which is suggested to have formed about 3,600 to 3,100 million years ago.
Ur joined with the continents Nena and Atlantica about 1,000 million years ago (1 billion) to form the supercontinent Rodinia. Ur survived as a single unit until it was sundered when the supercontinent Pangaea broke apart into Laurasia and Gondwana.
Rocks that made up Ur are now parts of Africa, Australia, and India.
In the early period of Ur's existence, it was probably the only continent on Earth, and as such is considered a supercontinent, though it was probably smaller than present-day Australia.
When Ur was the only continent on Earth, all other land was in the form of small granite islands and small land-masses like Kenorland that were not large enough to be continents.
Ur also called Ur/Web is an open source functional programming language specific for web development, created by Adam Chlipala at the Massachusetts Institute of Technology that from a single program produces server code, browser client code and SQL code specific for the chosen database backend.
Ur supports a powerful kind of metaprogramming based on row types.
Ur/Web is Ur plus a special standard library and associated rules for parsing and optimization. Ur/Web supports construction of dynamic web applications backed by SQL databases. The signature of the standard library is such that well-typed Ur/Web programs "don't go wrong" in a very broad sense. Not only do they not crash during particular page generations, but they also may not:
Ur is the Basque word for 'water'.
This root may be found in many place names and some derivates as: