coordination number
An identity number for people who are not, or not yet, entered in the Swedish population register, for example someone who works or studies here for less than a year. It lets agencies, employers and banks identify you even though you have no personnummer.
You can apply for one yourself if you plan to stay less than a year, have a connection to Sweden and can show why you need it. You must also attend an identity check at a service centre; in some cases a Swedish embassy can do it. Some authorities can also request a number for you.
If you later move here for a year or more, you report your move instead, and the coordination number is replaced by a personnummer.