Vocabulary What does 火薬 (かやく, kayaku) mean? 火薬 (かやく, kayaku) means gunpowder; powder. Quick factsReadingかやくRomajikayakuPart of speechnoun 火薬かやくkayakugunpowder; powder1noun gunpowder; powderKanji in this word火fire薬medicine, drug