"The Dharma is a key concept in Buddhism and Hinduism. In English there are generally two distinct (but connected) meanings. The first is that The Dharma (when capitalized) simply means the collective teachings of The Buddha. In this respect, you might think of the Dharma as simply menaing "The Teachings."
The second meaning is usually associated with the lowercase dharma, and translates as "the way things are." This may seem overly vague, until you understand that the word "dharma" has been used to imply "the laws of nature" or "that which sustains the universe." Sometimes it is synonomys with the English word nature."
"The dharma is touched upon at length in The Bhagavadgita (The Song of God), a section of the epic poem The Mahabharata. In it, Krishna explains the meaning of righteousness in sustaining the world order. It is implied that everyone has a path that they must follow in order to uphold righteousness and lead to their individual salvation. Krishna stated that of the three paths that lead to salvation - yoga and ascetic practices, bhakti or devotion, and Dharma or wholesome activities according to your role - it was the latter that was most effective because it contribute to both the individual and the world as a whole, while the two former practices only helped the individual.
Those familiar with Buddhism know that the dharma was the main focus of His meditations. These were the main characteristics of the dharma:
1) Namely, that it was infinite and spanned both the material (mundane) and spiritual (supra-mundane) worlds.
2) The dharma could be thought of as the mental "sense." That is to say, while the eye has sight and the ear has sound and the nose has smell, the mind has dharma.
3) The dharma was the carrier of goodness and wholesomeness, and thus the word dharma could be used to imply a good sense, while the word adharma would imply a bad sense.
4) Dharma was a person's duty, those acts which were fit to be carried out according to their responsibilities.
5) Dharma is a permanent universal truth, including the laws of nature and the nature of laws.
http://www.siamese-dream.com/reference/dharma.html