The term Dharma is one of the most intractable terms in Hindu philosophy. Derived from the root dhar (Dhri) to uphold, sustain, support, the term Dharma denotes ‘that which hold together the different aspects and qualities of an object into a whole.’ (Dharanat Dharmam Ithayahu, Dharmena Vidhritah Prajah.’
Ordinarily, the term Dharma has been translated as religious code, as righteousness, as a system of morality, as duty, as charity etc. But the original Sanskrit term has a special connotation of its own which is not captured by any one of these renderings. The best rendering of the term Dharma that I have met with so far is, ‘the Law of Being’ meaning, ‘that which makes a thing or being what it is.’ For example, it is the Dharma of the fire to burn, of the sun to shine, etc.
Dharma means, therefore, not merely righteousness or goodness but it indicates the essential nature of anything, without which it cannot retain its independent existence. For example, a cold dark sun is impossible, as heat and light are the Dharmas of the sun. Similarly if we are to live as truly dynamic men in the world, we can only do so by being faithful to our true nature, and the Bhagavad Gita explains ‘to me my Dharma.’
(Source: The Holy Geeta commentary by Swami Chinmayananda – 2001 edition – page 12)