Short answer. From Persian, and it originally meant a wall. The Old Iranian compound behind it is pairi-daēza-, “around” plus “to build a wall,” so literally a walled enclosure: the royal parks and hunting grounds of the Persian nobility. Greeks who saw them borrowed the word as parádeisos. Hebrew borrowed it as pardēs, where it appears three times and means an orchard, with no religious content at all. Only later, in the Greek translation of the Hebrew Bible, does it become the word for the garden of Eden, and later still, in the New Testament, a word for the destination of the righteous dead.
Tier note: the etymology and the borrowing route are bedrock, uncontested in the philological literature and checkable in any standard lexicon. What that borrowing implies is a separate question, and the distinction between the two is the entire point of the last section. A word crossing a border is not the same event as an idea crossing one.
A wall, before it was a garden
The root is Old Iranian. Avestan has pairi-daēza-, and Old Persian a corresponding form, built from pairi, “around,” and a root meaning to form or build up a wall. The literal sense is a walled enclosure. The wall is the word; the garden is what happened to be inside it.
What was inside, in practice, were the enclosed parks of the Achaemenid nobility: orchards, watercourses, game for hunting, order imposed on a landscape and kept behind a boundary. Greeks who served in or travelled through the empire found these remarkable enough to need a word for, and Xenophon uses parádeisos for exactly that, a Persian royal park.
So the first thing the word ever meant was a piece of imperial landscape architecture.
In Hebrew it is just an orchard
The Hebrew Bible contains the loanword pardēs exactly three times, and this is the part most readers find surprising, because in all three it is entirely ordinary.
Nehemiah 2:8 has Nehemiah asking the Persian king for timber from “the king's pardēs,” which is a royal forest or park, an administrative request inside the Persian bureaucracy. Ecclesiastes 2:5 has the speaker making himself gardens and pardesim and planting fruit trees in them. Song of Songs 4:13 uses it of a pardēs of pomegranates.
No afterlife. No Eden. No theology whatever. Three orchards. And note where the word shows up: in late books, written or set in the Persian period, which is exactly where you would expect Persian administrative vocabulary to appear.
How an orchard became heaven
The shift happens in translation. When the Hebrew Bible was rendered into Greek, the translators needed a word for the garden God plants in Genesis 2, and they reached for parádeisos. That is a reasonable choice for an enclosed, planted, watered space. But it welded a Persian loanword onto the story of Eden permanently.
From there the drift is short. In Second Temple literature the garden of Eden becomes a place the righteous might be kept or restored to, and by the New Testament parádeisos can mean the destination of the righteous dead: Jesus tells the man beside him they will be there today (Luke 23:43), Paul is caught up into it (2 Corinthians 12:4), and Revelation 2:7 places the tree of life in it.
A word for the Persian king's hunting park had become the Christian word for heaven, and the route ran through a translation decision.
The part that does not follow
Here is where this page parts company with the popular version of itself, and the distinction matters more than the etymology does.
That the word is Persian is certain. That the idea is Persian does not follow from it. The three Hebrew uses carry no theology at all, which is the strongest evidence available that what crossed the border first was vocabulary, not doctrine. Languages borrow words for things they encounter, and Judeans under Achaemenid rule encountered Persian parks. Nothing about that requires them to have borrowed an afterlife.
English is full of this. “Assassin,” “algebra” and “alcohol” are Arabic; nobody concludes that English speakers imported Islamic theology along with them. A loanword is evidence of contact, and contact is the beginning of an argument rather than the end of one.
What pardēs does contribute is narrower and more interesting: it is one of a small number of Iranian loanwords in the Hebrew Bible that later carry theological weight, which is the specific thing a critic would say never happened. That argument, with the measured distribution behind it, is at The Persian Passband, and the influence question is graded rather than asserted at Did Zoroastrianism Influence Judaism?.
The afterlife of the word itself
One coda, because it is a good one. In later Jewish mysticism the same consonants are read as an acronym, PaRDeS: peshat the plain sense, remez the hinted, derash the sought, sod the secret. Four levels of reading a text, named after a walled garden.
That is a later interpretive tradition rather than an etymology, and it should not be presented as one. But it is a fitting end for a word that started as a wall around a Persian orchard: it ends up naming the practice of reading through the surface of a text to what is enclosed inside it. See What is the Zohar?.
Common questions
What does the word paradise literally mean?
A walled enclosure. It comes from the Old Iranian compound pairi-daēza-, from pairi meaning “around” and a root meaning to build up or form a wall. It described the enclosed parks, orchards and hunting grounds of the Persian nobility. The garden associations came from what was kept inside the wall; the word itself names the boundary.
Is paradise a Persian word?
Yes, and this is not seriously disputed. It is Old Iranian in origin, attested in Avestan as pairi-daēza-, borrowed into Greek as parádeisos (Xenophon uses it of Persian royal parks) and into Hebrew as pardēs. English received it through Latin paradisus and French. The etymology is standard in the lexicons.
How many times does pardes appear in the Hebrew Bible?
Three: Nehemiah 2:8, where Nehemiah requests timber from the Persian king's pardēs; Ecclesiastes 2:5, where the speaker plants gardens and orchards; and Song of Songs 4:13, a pardēs of pomegranates. In all three it means an ordinary orchard or park, with no religious sense at all. All three are in late books associated with the Persian period.
When did paradise start to mean heaven?
Through Greek, in stages. The Septuagint translators used parádeisos for the garden God plants in Genesis 2, attaching the word to Eden. Second Temple literature then developed Eden as a place the righteous might be restored to, and by the New Testament the word can mean the destination of the righteous dead, as in Luke 23:43, 2 Corinthians 12:4 and Revelation 2:7. The move from orchard to afterlife runs through a translation choice.
Does the word prove Zoroastrian influence on Judaism?
No, and the page is explicit about it. The word crossing is certain; the idea crossing is a separate claim that does not follow from it. The three Hebrew uses carry no theology whatever, which is itself the best evidence that what was borrowed was vocabulary rather than doctrine. English borrowed “algebra” and “alcohol” from Arabic without importing Islamic theology. A loanword establishes contact, and contact is where an argument starts.
What is PaRDeS in Kabbalah?
A later interpretive scheme that reads the same consonants as an acronym for four levels of reading scripture: peshat, the plain sense; remez, the hinted; derash, the sought or expounded; and sod, the secret. It is a tradition of interpretation rather than an etymology, and it should not be offered as an explanation of where the word came from. It is a fitting coincidence rather than a derivation.
Sources
Nehemiah 2:8; Ecclesiastes 2:5; Song of Songs 4:13; Genesis 2:8 (LXX); Luke 23:43; 2 Corinthians 12:4; Revelation 2:7. Xenophon, Anabasis and Oeconomicus, on Persian parks. Benjamin J. Noonan, Non-Semitic Loanwords in the Hebrew Bible (2019); standard lexica for Avestan pairi-daēza- and Old Persian; Martin Haspelmath & Uri Tadmor, Loanwords in the World's Languages (2009), for the borrowing taxonomy used in the passband work.