"From the time of the Achaemenid Empire, the idea of an earthly paradise spread through Persian literature and example to other cultures, both the Hellenistic gardens of the Seleucid Empire and the Ptolemies in Alexandria. The Avestan word pairidaēza-, Old Persian *paridaida-,[note 1] Median *paridaiza- (walled-around, i.e., a walled garden), was borrowed from Semitic: Akkadian pardesu (in Semitic it means cool weather, shaded place), variants of the Akkadian word found its way into Greek Ancient Greek: παράδεισος, translit. parádeisos, then rendered into the Latin paradīsus, and from there entered into European languages, e.g., French paradis, German Paradies, and English paradise. It also evolvedTemplate:29 January 2018 in Semitic languages, such as Hebrew (pardes), and Arabic (firdaws).[3]

As the word expresses, such gardens would have been enclosed. The garden's purpose was, and is, to provide a place for protected relaxation in a variety of manners: spiritual, and leisurely (such as meetings with friends), essentially a paradise on earth. The Common Iranian word for "enclosed space" was *pari-daiza- (Avestan pairi-daēza-), a term that was adopted by Christian mythology to describe the garden of Eden or Paradise on earth.[4]

The garden's construction may be formal (with an emphasis on structure) or casual (with an emphasis on nature), following several simple design rules. This allows a maximization, in terms of function and emotion, of what may be done in the garden."