Meaning

Hindu is Area Between - 

1. Himalayas (H)  
2. Indus River or Indian  Ocean (Indu)

https://freeglobaluniversity.blogspot.com/search/label/Himalayas

https://en.wikipedia.org/wiki/Indus_River

https://en.wikipedia.org/wiki/Indian_Ocean

the terms Hindu/ Hindi are also used as a cultural identity to denote people living on the other side of the Indus river, thus 

1. Poets like Iqbal, 
2. ministers like M.C.Chagla and 
3. organisations like the RSS

http://freeglobaluniversity.blogspot.com/search/label/RSS

to represent any person irrespective of religion (including practitioners of 

1. Hinduism, 
2. Muslims, 
3. Christians, 
4. Sikhs, 
5. Jains, 
6. Budhists, etc. 

http://freeglobaluniversity.blogspot.com/search/label/Secular

Hence it is Geographical Area Rather than Faith

https://freeglobaluniversity.blogspot.com/search/label/Bharat