The House of Lords is Parliament's second chamber.
Its main job is to 'double check' new laws to make sure they are fair and will work.
There are 675 members of the Lords. They are not elected. They come from many different backgrounds.
The House of Lords does not have the power to stop a new law that the commons wants, but it can delay it.
It can do this because bills must go through both Houses before they become 'Acts' (laws).