There is considerate debate among scholars as to the origins of the word Hindu. What they all agree on, however, is that the word Hindu was initially used as a geographic reference to the people who reside in the Indian sub-continent. It was much later that the term took a religious connotation.
The most popular origin theory for the word Hindu is that it is a corruption of 'Sindhu' or rather, a sound shift that was later adopted in a number of indigenous dialects as well.
The Persians coined it (S is replaced by H in Persian) to refer to those that lived beyond the mighty Sindhu River. There are references in the Zend Avestha and Bem Riyadh to 'Hapta Hindu' (Land of Seven Mighty Rivers). However, the Persians never used the word Hindu to refer to the religion of these people.
Some scholars hold that ancient Indian civilization did have a name of its own, prior to the arrival of Persians. A Sanskrit scholar, Swami Mangal Nathji, had found ancient Hindu writings called Birhannaradi Purana in Hoshiarpur (Punjab) which contained the verse:
Himalayam samarabhya yavat bindusarovaram Hindusthanamiti qyatan hi antaraksha-rayogatah
The country between Himalayas and Bindu Sarovar (Cape Commorin Sea) is Hindusthan derived by combining the first letter 'Hi' of Himalayas and the last compound letter 'ndu' of the word Bindu.
Aaasindo sindhu paryantham yasyabharatha bhoomikah Mathrubhuh pithrubhoochaiva sah vai hindurithismrithaah
A Malayalam (language spoken in the south west region of India comprising mostly Kerala) verse also connote the same meaning and reads as:
"Sapta sindhu muthal sindhu maha samudhram vareyulla bharatha bhoomi aarkkellamaano Mathru bhoomiyum pithru bhoomiyumayittullathu, avaraanu hindukkalaayi ariyappedunnathu"
Both indicate that whoever considers the land of Bharatha Bhoomi between Saptha Sindhu and the Indian Ocean as his motherland and fatherland is known as Hindu. This however finds difficulty as other scholars state that these are later interpolations into the texts and that the original texts did not have these references.
The real and ancient name of India is referred to as 'Bharatha Varsha'. There are numerous Vedic references in the Puranas, Mahabharata and other texts as well as common usage within the country and is agreed to by scholars.
Another theory is that it is derived from the Sanskrit word 'Hidi', which means to achieve one's objective, to acquire knowledge, to be progressive and ignore what is obstructive. Therefore, one who follows the spiritual path in order to acquire perfection through divine knowledge is known as 'Hindu'. However, the Sanskrit rules of grammar defined by Panini do not allow for a derivation of Hindu from the root Hidi.
- NB Pavgee, Self-Government in India, 1912