also: こうか
noun
world-destroying conflagration; kalpa-ending fire
Buddhist term for the great fire that destroys the world at the end of a kalpa. Used metaphorically for a massive, all-consuming fire or catastrophe.
仏教の経典には、劫火が世界を焼き尽くすと説かれている。
Buddhist scriptures teach that the kalpa-ending fire will consume the world.
その戦争はまるで劫火のように街を破壊した。
The war destroyed the city like a world-destroying conflagration.
大火 means a large fire or conflagration in a general sense, while 劫火 specifically refers to the Buddhist concept of the world-ending fire and carries a more mythological or catastrophic nuance.
From Buddhist terminology, composed of 劫 (kalpa, an immense period of time) and 火 (fire). The exact historical derivation is uncertain, but the term is firmly rooted in Buddhist cosmology.