This term has multiple meanings.
1) Exoterically, this is a conventional locution for either the Garden of Eden or of the heavenly afterlife.
2) It is also a metonym [an attribute of something used to stand in for the thing itself] for the mystical experience
3) The consonants, PRDS] can be read as an acronym for four methods of Scriptural interpretation: Pashat (authoritative), Remez (allegorical or philosophic), Drash (homiletical or midrashic), and Sod (esoteric or mystical). It also carries the connotation of sacred study en toto.