Wiktionary
ekpyrosis
n. (context philosophy English) The supposed periodic destruction of the universe
Wikipedia
Ekpyrosis
Ekpyrosis (; ekpurōsis, "conflagration") is a Stoic belief in the periodic destruction of the cosmos by a great conflagration every Great Year. The cosmos is then recreated ( palingenesis) only to be destroyed again at the end of the new cycle. This form of catastrophe is the opposite of kataklysmos (κατακλυσμός, "inundation"), the destruction of the earth by water.
The concept of ekpyrosis is attributed to Chrysippus by Plutarch.