火灾 (huǒ zāi) literally combines 火 (‘fire’) and 灾 (‘disaster’ or ‘calamity’), meaning a destructive fire that causes harm to people, property, or the environment. It refers specifically to uncontrolled fires requiring emergency response — not small, contained flames like cooking fires or candles. In Chinese, this term carries serious connotation and is used in official reports, safety announcements, news headlines, and public education materials.

The word emphasizes the scale and danger of the event: even a small blaze becomes a 火灾 when it spreads beyond control or threatens life or infrastructure. It is commonly paired with verbs like 发生 (to occur), 引起 (to cause), 扑灭 (to extinguish), or prevent with 预防. Unlike the more general word 火 (fire), 火灾 always implies damage, risk, or emergency response.