Dharma is a Sanskrit word having different meanings being used according to the situation. It is also loosely translated as 'faith' which is not correct. Faith is based on belief, Dharma is based on Truth.
At times it is used in the sense of justice and in other senses it is used as donation. By righteous character man becomes Godly otherwise the same man becomes a devil.
Dharma can be interpreted in many ways, but it basically means the 'true and natural' property.
And when it is used to express eternal laws of this Universe that govern this Nature that includes nano particles, microbes to planets, eco systems, vast galaxies, etc., and when it refers to the unchangeable perfect laws of Karma which form the basis of all causes and effects in this world, the wise sages of India called this Dharma as 'Sanatana Dharma (Sanātana Dharma)' which means 'the eternal laws of righteousness'.
Dharma is the moral law, which guides one's life. It is the very foundation of human life. It upholds the natural order of the Universe. The root of Dharma is compassion. Austerity, purity, compassion and truthfulness are essential for living on a Dharmic path. Non-violence, truth, non-coveting, purity of body and mind, control of senses are the essence of Dharma.