For example, the Fire signs are either Cardinal Fire, Fixed Fire or Mutable Fire. So are the Earth, Water and Air signs. The subtle differences affect the way a planet expresses its energy. There is another factor. Each sign has a traditional planetary 'ruler' which adds its influence to any planet in the sign.
Houses are fields of experience.
These are both outer, or material experiences and inner or psychological experiences. They are defined by certain mathematical relationships between a location on earth and the solar system. There are 12 houses. There are several different methods ways to calculate houses. The system we have used is Placidus.