When did we get the name "Sanatan Dharma"? Is "Sanathan Dharma" and Hinduism one and the same? I see hardly people know about Sanatan Dharma. Mostly in North India, people know it and in the South, people are somewhat ignorant about this.
That phrase came from Sage Valmiki himself. In Valmiki Ramayana, it occurs several times. Here is one instance -
Nrusamsam Anrusamsam va prajA rakshaNa kAranAth, pAthakam va sa dosham va kartavyam rakshatA sadA, rAjyabhAra niyuktAnAm ee-eshA dharma sanAthana ha....
Meaning: For the reason of protecting people, a protector always has to execute such deed, whether it is ruthless/cruel or humane, sinful or vilifying. To the nominee who bears the burden of ruling a kingdom this is the eternal path of righteous conduct..
Sanatana dharma is the same as Dharma sanatanaha. The former is used when emphasizing dharma as a priority, and the latter is used when emphasizing the eternality aspect of it as a priority.
The word 'Hinduism' didn't exist until recently. Because as you know 'Hindu' itself is a Persian word for 'Sindhu'. But yes, Hinduism is the current avataar of Sanatana Dharma. And I know many South Indians who know this correct term for our religion.
Varnashrama dharma / sanadhana dharma (the following is from Gandhiji's speech delivered on 16/09-1927 at Thanjavur) "in my opinion there is no such thing as inherited or acquired superiority." I believe in the rock-bottom doctrine of advaita and my interpretation of advaita excludes totally any idea of superiority at any stage, whatsoever.