A name English still keeps in reserve
In present-day English, Hindustan is a geographical name rather than a word people reach for every day. Dictionaries still list several scopes for it. It can mean the northern Indian plain north of the Deccan, the belt drained by the Indus, Ganges, and Brahmaputra. It can mean the Indian subcontinent as a whole. In looser later use it can also stand for the Republic of India. Hindi and Urdu keep the same compound as a living country name, which is one reason the English form never fully disappeared once India became the usual official label in Western languages.
Those overlapping senses are not a modern muddle. The name was a moving target from the start, because it began as a Persian description of a river country and only later covered a much larger map. The origin of the word Hindustan is Persian, even though the first half of the compound ultimately points back to the Indus.
Borrowed in the age of company ships
English took the form in the early seventeenth century. Handbook dates cluster in the 1610s; the earliest citation in a major historical dictionary of English is 1622, in a report on the kingdom of Magor. Both sit inside the same window of East India Company travel and trade writing. The immediate source is Persian Hindūstān, literally the country of the Hindus. English almost certainly met the compound through Hindi and Urdu as well, which had already borrowed the Persian name.
Older spellings show how unsettled the loan still was. Writers used Hindostan and Hindoostan, and even Indostan, a form already in print in the 1590s. Those are not different names. They are attempts to catch a Persian and Hindustani pronunciation with the letters English then had for foreign place-names. The related adjective and language name Hindustani appears later, in the eighteenth century, and was long used in English for what is now more often called Urdu, or for the broader Hindi–Urdu continuum.
The English word is a borrowing, not an inherited Germanic compound. Native English already had India, from Greek and Latin, built on the same river name by a different route. Hindustan arrived as a second, Persian-shaped label for overlapping territory.
Hindu, Sindhu, and the suffix that means a standing-place
The first half is Persian Hindu, earlier an ethnic and geographic label meaning Indian, from Hind, Persia’s name for the land of the Indus. That Hind is the Iranian counterpart of Sanskrit Sindhu, the name of the Indus River and of the country around it. Iranian languages regularly turned an inherited s into h, so Sindhu appears in Old Persian as Hinduš, the Achaemenid name for the Indus province after Darius I annexed the lower valley in the late sixth century BCE. The Avesta already has hapta hindu where Vedic tradition has sapta sindhava, the land of seven rivers. The same Iranian form, once Greek dropped the initial h, is the source of India itself.
Sanskrit sindhu means river, stream, or sea, and by extension the Indus. Scholars do not all agree on a deeper analysis. Some connect it with a root for flowing water. Others link it to a root meaning to ward off, which would give a sense closer to barrier or natural boundary. That disagreement belongs to the river-name, not to the later Persian compound, and it is safer to leave it open.
The second half is transparent. Persian -stān means country or place, literally where one stands. It comes from an Indo-Iranian word for place, itself from the widespread Indo-European root meaning to stand. English speakers know the same suffix from Afghanistan, Pakistan, Kazakhstan, and a long list of other country names. In Middle Persian, probably from around the first century CE, that suffix was added to Hindu, producing Hindūstān. An inscription of the Sasanian king Shapur I at Naqsh-e Rostam, dated about 262 CE, already uses the name for the Sindh region. From the lower Indus the label gradually stretched, as India did in Greek and Latin, toward more or less the whole subcontinent.
So the morphology is real, not a later story invented to make the parts look neat: a people-or-river name plus a place suffix. What changed was not the parts, but how much land those parts were allowed to cover.
From a river province to a country name
In the early Persian use the name still pointed at the Indus country. Under the Delhi Sultanate and the Mughals it often meant the rulers’ Indian dominion, especially the north Indian heartland around Delhi, rather than the far south. Arabic had a related form, al-Hind, which at times covered a still wider belt from the Makran coast toward Southeast Asia before it, too, settled on the subcontinent.
English usage in the colonial centuries tracked those older political senses and then added new contrasts. Nineteenth-century English often treated Hindustan as another name for the subcontinent, used beside India. It could also mean specifically the Hindi-speaking Ganges country, or the predominantly Hindu parts of the region as opposed to Muslim-majority lands that later became Pakistan. Those narrower senses are now dated in English. What survives in casual speech, and what remains lively in Hindustani, is the sense India.
Cognates make the family easy to see. Hindi and Urdu keep हिंदुस्तान and ہندوستان. Persian still has Hendustān. Spanish Indostán and Russian Indostan show the same compound with a slightly different vowel. Greek and Latin India, and English India, are not compounds with -stan, but they rest on the same Sindhu / Hindu river name after it passed through Persian into Greek.
The durable fact is small and physical. Long before the word named a modern republic, it named a standing-place beside a river. Persian speakers called that river-country the land of the Hindus; English borrowed the compound in the early 1600s; and the map under the name kept growing until it could mean, depending on the century, Sindh, north India, or India at large.