Due to the inquiry of Margaret, I have decided to explain what a cantilever is in architecture. In its simplest definition, a cantilever is a beam that is supported at only one end. In the photo below, the dashed blue lines represent the placement of a typical beam. However, with their nonexistence, the floor above is "cantilevered" over the space below. This creates an open plan below and takes away the obstruction a column sometimes places on the plan. Frank Lloyd Wright was a master of this and his Falling Water house was a prime example of this.
Falling Water by Frank Lloyd Wright