Freemasonry is a fraternal organisation that arose from the loose organization of medieval masons (i.e. stone workers) working in the medieval building industry (i.e. craft workers involved in medieval stone work).Early organizational forms included lodges,incorporation, and craft guilds. Early Freemasonry based on craft labor is known as Operative Freemasonry.
Freemasonry now exists in various forms all over the world, with a membership estimated at around six million, including approximately 150,000 under the jurisdictions of the Grand Lodge of Scotland and Grand Lodge of Ireland, over a quarter of a million under the jurisdiction of the United Grand Lodge of England, and just under two million in the United States.
The fraternity is administratively organised into independent Grand Lodges or sometimes Orients, each of which governs its own jurisdiction, which consists of subordinate (or constituent) Lodges. The various Grand Lodges recognize each other, or not, based upon adherence to landmarks. A Grand Lodge will usually deem other Grand Lodges who share common landmarks to be regular, and those that do not to be irregular or clandestine.
There are also append-ant bodies, which are organisations related to the main branch of Freemasonry, but with their own independent administration.