'death-watch' originates from English, specifically a compound of 'death' + 'watch', where 'death' meant 'the end of life' and 'watch' meant 'a period of vigil or keeping watch.'

'death-watch' developed in Early Modern English as a compound referring to the act of watching beside the dying; later (17th–18th c.) the name was extended to certain wood-boring beetles whose ticking noises were associated with such vigils, leading to the modern use for both the vigil and the beetle.

Initially, it meant 'a vigil kept over someone near death'; over time it also came to refer to the beetle (and its ticking) because people associated the beetle's sound with nights of watching the dying.