palingenesis

Probably a variant of palingenesia +‎ -genesis (suffix meaning ‘origin; production’). Palingenesia is a learned borrowing from Late Latin palingenesia (“rebirth; regeneration”), from Koine Greek παλιγγενεσία (palingenesía, “rebirth”), from Ancient Greek πᾰ́λῐν (pắlĭn, “again, anew, once more”) (ultimately from Proto-Indo-European *kʷel- (“to turn (end-over-end); to revolve around; to dwell, sojourn”)) + γένεσις (génesis, “creation; manner of birth; origin, source”) (ultimately from Proto-Indo-European *ǵenh₁- (“to beget; to give birth; to produce”)) + -ῐ́ᾱ (-ĭ́ā, suffix forming feminine abstract nouns). By surface analysis, palin- +‎ genesis.

Sense 2 (“apparent repetition, during the development of a single embryo, of changes that occurred previously in the evolution of its species”) is from German Palingenesis; while sense 3 (“regeneration of magma by the melting of metamorphic rocks”) is from Swedish palingenes. Both are derived from the Greek word: see above.

The plural form is probably from palingenesis + Latin genesēs (a plural form of genesis).