HINDU: “HI” for himalaya & “INDU” for Indu (Indian Ocean)/sagar/hind mahasagar.
In ancient india the people of this land, from himalaya to ocean are called Hindu. at those time all are of same religion. i.e., the ancient way of life in these lands as per Vedas the sanatan dharma, the seekers of truth.
Even before Mohammed and Jesus, the word Hindu was used in the sense of gentle, beautiful, amiable, adorned, rightful and killer of enemies.
When Alexandra came to India, he had the desire to visit Hindukush which means Hindkoot Parvat.
In one of the scripture of Parsis (Zoroastrians), ‘Shaatir’, Hindu word is mentioned.
In Avesta, there are so many Vedic words which is hundreds of years old before Alexandar in which Hindu word is used.
The city Balakh was ealier called Hindwar
‘Sa’ and ‘Ha’ are similar according to Rigveda and if we look at it from this perspective, then according to Bhavishya Puran, for Sindhusthan or Hindusthan or Hindustan, this word is used and this is called the pefect country of Aryas.
In Kalika Purana, ‘Hindvo’ word is used, In ‘Shargandhar Paddhati’, Hindvo word is used but calling themselves ‘Ved-margiya’, people treading on path of Vedas were called Hindu’.
Hindu is the name for Aryas, ‘Indu’ and ‘Sindhu’ were considered synonyms, both are Sanskrit words.
If we follow ‘Brahaspati Agama’, then the area is also identified. In ‘Brahspati Agama’, very clearly, Hindustan word is used.
In Aashvamedhika Parva of Mahabharata, the ‘Aryavarta’ only is called Hindusthan or Hindustan.
As per Brahaspati, one who is virtuos, who remains away from violence but capable of destroying anarchic elements, who is protector of Vedas and cattle, that person is Hindu.
This should also be understood that in ‘Ramkosha’ and ‘Parijaatharan’ drama also, Hindu word is used.
An expansive definition of Hindus is available as per ‘Madhaviya digvijaya’ – The person who has accepted seed mantra of Vedas ‘Om’ as his mantra, who believes in rebirth, who worships cow, who worships Ganga and as per Indian tradition, believes Vedic rishis as his Guru and is capable of killing the violent animals and alongwith are Udbhashak of Kshatriya Dharma, those are called Hindu.
If we ponder, then in Rigveda too, Hindu word is used, in it, ‘Hi’ and ‘ndu’ both are used in the sense of cow-worhippers.
That’s how, I explained through many examples, that it is not a derogatory work given by Muslims and infact, before Muslims, Alexandra came to India, even before him Hindu word is used in Zoroastrians Scriptures.
In the scriptures written by Ved Vyasa, in repositories like ‘Vividh Medani’, in Puranas like Kalika Purana, Hindu word is used. And there is an excellent way to verify its meaning.
Please everyone check it for every ancient land which was connected to India through trade or through spread of religion, science, maths, technology, medicine, or any way. check it by yourself in Google Translation, type one side india and on otherside choose different languages and then read & hear their pronunciation there at the option below.
Hence, in this situation, Sindhu and Indu are considered synonyms.
Greeks at the time of Alexander the Great at 330 BCE, Megasthenes call his book about India “indica” (इंडिका/इन्दूका/हिन्दूका) which came from the root word INDU/INDUS (इन्दू/इन्दुस्), which is deformation of word HINDU/HINDUS (हिन्दू/हिन्दुस्).
Chinese even today call India as “Yìndù (इन्दू)”/“HINDU (हिन्दू)”.
Japanese call India even today “Indo (इंदो)”.
In Arabic, India still called as “alhind” but its pronunciation is (अल हिन्दू )”.
In korean they call us “Indooo (इंदो)”.
Like today, the political parties are called, BJP (Bhartitya Janta Party), SP (Samajwadi Party), BSP (Bahujan Samaj Party), etc, in the same way, according to those times, in Rigveda also, for a cow-worshipper, the word Hindu is used. In Atharvveda, it is used as it is.
So, the word Hindu is Vedic, ancient, available in dictionaries and foreigners keep calling them Hindu only.
https://www.sanskritimagazine.com/indian-religions/hinduism/how-old-is-the-word-hindu/
https://www.youtube.com/watch?v=fcB3vh2_Be8
https://www.youtube.com/watch?v=Bbn5jdiyHnA