Yin & Yang
Yin yang are the two opposing forces in the universe, most often thought of as good vs. evil, black and white, hot and cold, these are some of the antonyms used to express the meaning of yin and yang. Technically you cannot have one with out the other. There are many different attributes to the yin yang theory.
Yang is identified as being more ACTIVE, of the two energies. It can be described as HOT, like a FIRE. It has distinguishable qualities that are related to the MALE gender. Yang is an energy of the DAYTIME, it is full of LIFE, and MOVEMENT. Yang is the life of the PARTY. It is FAST moving energy.
Yin is SLOW and SEDATE, it has the opposite of life force moving through it, it is DEATH. Yin is the SILENCE of the library, the SOLITUDE of confinement. It is UNMOVING, and STILL. Yin is representative of FEMALE qualities. It is NIGHT TIME, COLD, WINTER and lacking the life force of energy.
Yin and yang are really the elements of balance within feng shui, you need one to have the other and the theory is a wide topic. It is more than just understanding up and down, as your understanding of feng shui deepens so will your outlook on yin yang.
One example of very still or YIN energy is a cemetery. This is definitely a STILL area with no LIFE FORCE. It is a SAD environment. Of course this is an extreme representation of YIN energy.
A very YANG energy would be a wedding or a graduation. There is celebration and a lot of LIFE fORCE energy. Tons of MOVEMENT would be taking place with a lot of people HAPPY.
While these are both very definitive characteristics of yin yang, it is helpful to look at the theory on a smaller scale. Remember, you cannot have one without the other.
A dwelling has its own representation of yin yang right in it. There are yang or active areas of the house, just as there are yin or still areas. Typically the yang areas are the common areas and the yin is the more quiet areas. Bedrooms and bathrooms would be considered yin.
It is important to gain a good understanding of yin yang theory if you have a deep interest in feng shui, one of the best ways is to just look around at your environment and start where you are, start identifying yin and yang as you take note of them.