Dharma comes from the root dhṛ to hold, to sustain, to bear. It names what holds things together. Not what you feel called to do. Not your life’s purpose. What sustains the structure of things when beings act in accordance with their nature. This distinction matters because the modern yoga world has inherited a reading of Dharma that is almost entirely personal. Your Dharma. Your calling. Your path. The tradition uses the word at a far wider scale than this, and the personal dimension only makes sense when the wider scales are in view.
Before Dharma, the Ṝgveda gives us a prior concept - Ṛta. It is the cosmic order that underlies all of manifest reality, the way things move when nothing is obstructing them. The sun rises, the seasons turn, the river goes to the sea - none of this is upheld by agreement or choice. It simply is. Ṛta names that inherent order. Dharma is what happens when conscious beings, human beings, in particular bring their action into alignment with it. In the Ṝgveda, Varuṇa is the guardian of Ṛta. He is the one who perceives when the order has been violated, when someone has stepped out of alignment. A ṛṣi who has acted against the order does not go to Varuṇa with arguments or reasons. He goes with honesty, acknowledging what he did, asking to be restored. There is no negotiating with Ṛta. You either move with it or you do not.