first-hand contract
A rental contract directly with the landlord who owns the building, as opposed to renting from someone who rents it themselves (second hand). It is the most secure way to rent: you have strong protection against being given notice, and you can, with permission, sublet or swap the flat.
In the large cities first-hand contracts are mostly offered through housing queues (bostadskö) run by municipalities or landlords, often after years of waiting, which is why so many newcomers start in second-hand housing.
Never pay anyone for a first-hand contract. Buying or selling a rental contract is against the law.