Religion is a collection of cultural and belief system that establishes symbols that relate humanity to spirituality and sometime to moral values.
According to Swami Rama: The words "religion" and "dharma" denote two entirely different concepts and perspectives. Religion is comprised of rituals, customs, and dogmas surviving on the basis of fear and blind faith. Dharma--a word, unfortunately, with no English equivalent--encapsulates those great laws and disciplines that uphold, sustain, and ultimately lead humanity to the sublime heights of worldly and spiritual glory. Established in the name of God, a religion is an institution that requires a growing number of adherents for its expansion and future existence. A religion discriminates against human beings who do not belong to its particular order and condemns their way of living and being, whereas dharma is eternal, looking for no followers for its propagation. With no discrimination whatsoever, it leads a human being beyond the realms of man-made, institutionalized dictums. Instead of creating fear of God, it makes God manifest in the human heart, not in an anthropomorphic form, but as the absolute and universal One in whom all diversities reside in perfect harmony.
The Upanishads saw 'Dharma' as the universal principle of law, order, harmony, all in all truth, that sprang first from Brahman.
In the Brihadaranyaka's own words:
Verily, that which is Dharma is truth.
'Satyam vada, Dharmam chara'
Literally means, Speak the Truth and Practice Dharma.
Ancient Hindu scriptures emphasize the importance of 'Satya' and 'Dharma'. Satya is the eternal, absolute and unchanging truth. Dharma is often translated as righteousness, Law or Natural Law.
When you add language and living style (traditions, practices and habits) to Dharma, it becomes Culture.