The word Dharma comes from the root word "dhri" which is to carry or sustain. To live a Dharmic life we have to sustain the proper way of existence by behaving righteously. We have a responsibility to uphold morals, to give charity when appropriate, and to be of service to others. These are principals that exist in all cultures and define a natural way of life. My faviorite quote on Dharma from Mahabharata.
Tadrisho ayam anuprashno yatra dharmaha sudurlabaha
Dushkamha pralisankhyatum tatkenatra vysvasyathi
Prabhavarthaya bhutanam dharmapravachanam kritam
Yasyat prabhavasamyuktaha sa dharma iti nischayaha.
SHANTHI PARVA - 109-9-11
It is most difficult to define Dharma.
Dharma has been explained to be that which helps the upliftment of living beings.
Therefore, that which ensures the welfare of living beings is surely Dharma.
The learned rishis have declared that which sustains is Dharma.