[nzsdqcms] plural of apocalypse in Ancient Greek

Ancient Greek:

nominative singular: apokalypsis
nominative dual: apokalypsei
nominative plural: apokalypseis

other declensions (other cases and numbers).

made famous by Buffy.

the English word apocalypse has been modified from the Ancient Greek word apokalypsis, so the Ancient Greek plural is not transferable to English.  therefore, it is up to English to choose how to pluralize what is now an English word according to English conventions: I'm choosing apocalypses.

(also, the meaning has changed in English: the Ancient Greek word meant only the revelation of divine knowledge, most famously about the end of the world.  the modern English meaning, ignoring pedants who insist on the ancient meaning, is the end of the world itself.)

Ancient Greek had noun numbers singular (exactly 1), dual (exactly 2 in a situation for which 2 is natural, e.g., 2 eyes), and plural (2 or more, sometimes 3 or more).  if God and Satan reveal the end of the world in separate but related apocalypses, use the dual number in this situation, not plural.  if God reveals the end of the world to many prophets, but only 2 manage to write it down, use the plural, not dual.  "plural of apocalypse" is therefore quite an interesting question (dual or plural) depending on the circumstances of the apocalypses.

note: Ancient Greek was dead by the time the Book of Revelation (a.k.a. Book of Apocalypse) was written, replaced by Biblical Greek (Koine Greek).

pendantically, a post-apocalyptic world is merely one in which how the world will end has been communicated (revealed).  the Book of Revelation exists, so we have been living in a post-apocalyptic world for 2000 years.