That's not a surprising question. Even though Masons (Freemasons) are members of the largest and oldest fraternity in the world and even though almost everyone has a father or grandfather or uncle who was a Mason, many people aren't quite certain just who Masons are. A Mason is a member of a fraternity known as Masonry.
Masonry is the oldest fraternity in the world. No one knows just how old it is because the actual origins have been lost in time. Probably, it arose from the guilds of stonemasons who built the castles and cathedrals of the Middle Ages. Possibly, they were influenced by the Knights Templar, a group of Christian warrior monks formed in 1118 to help protect pilgrims making trips to the Holy Land.
In 1717, Masonry created a formal organization in England when the first Grand Lodge was formed. A Grand lodge is the administrative body in charge of Masonry in some geographical area. In the United States, there is a Grand Lodge in each state and the District of Columbia. Local organizations of Masons are called lodges. There are about 13,200 lodges in the United States.
By 1731, when Benjamin Franklin joined the fraternity, there were already several lodges in the Colonies and masonry spread rapidly as America expanded west. In addition to Franklin, many of the Founding Fathers - men such as George Washington, Paul Revere, Joseph Warren and John Hancock - were masons. Masons and Masonry played an important part in the Revolutionary War and an even more important part in the Constitutional Convention and the debates surrounding the ratification of the Bill of Rights. Many of those debates were held in Masonic lodges.
The word "lodge" means both a group of Masons meeting in some place and the room or building in which they meet. Masonic buildings are also sometimes called "temples" because much of the symbolism masonry uses to teach its lessons comes from the building of King Solomon's Temple in the Holy Land. The term "lodge" itself comes from the structures which the stonemasons built against the sides of the cathedrals during construction. In winter, when building had to stop, they lived in these lodges and worked at carving stone.
Since Masonry came to America from England, we still use the English floorplan for the lodge room as well as English titles for the officers. The Worshipful Master of the Lodge sits in the East. "Worshipful" is an English term of respect which means the same thing as "Honorable". He is called the Master of the lodge for the same reason that the leader of an orchestra is called the "Concert Master". It's simply an older term for "Leader". In other organizations he would be called "President".
Every lodge has an altar holding a "Volume of the Sacred law". In the United States it is almost always a Bible.