How to say "combustion" in Japanese

• 燃焼ねんしょうJLPT N1approx.Common
  noun, suru verb, intransitive verbThe word for combustion as a process of burning, as described in chemistry or engineering; it also covers burning generally, so it serves for 'burning' as well as 'combustion'.
  この種しゅの汚染おせん物質ぶっしつは主ぬしとして自動車じどうしゃエンジンの燃焼ねんしょうから生うまれる。↗

  Pollutants like this derive mainly from the combustion of fuel in car engines.
• 発火はっかCommon
  noun, suru verb, intransitive verbCenters on ignition, the moment something catches fire and starts to burn, rather than combustion as an ongoing process. For that process, 燃焼 is the word you want.

Use 燃焼 for combustion as the process of burning, especially in scientific or technical description; use 発火 for ignition, the moment something catches fire, when 'combustion' refers to that onset rather than the burning itself.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 燃焼ねんしょうburning
• 発火はっかignition