'灭火器' literally combines three characters: '灭' (to extinguish), '火' (fire), and '器' (device or instrument). Together, they form a compound noun meaning 'fire extinguisher' — a portable device designed to put out small fires. It is commonly found in offices, schools, apartments, and vehicles, and is an essential safety tool in fire prevention systems.

In everyday Chinese, 灭火器 appears in safety instructions, emergency drills, and public signage. Its usage is formal yet practical — you’ll see it on labels, in manuals, and during fire-safety training. Unlike more technical terms like '消防设备' (fire-fighting equipment), 灭火器 specifically refers to handheld or wheeled units meant for immediate, localized fire suppression — not large-scale firefighting apparatuses used by professionals.