'deathwatch' originates from English, a compound of the words 'death' and 'watch' (where 'death' comes from Old English 'dēaþ' and 'watch' from Old English 'wæcce'/'wæccan').

'deathwatch' appeared in Middle English in compounds like 'dethwacche' or similar spellings and developed into the modern English 'deathwatch'; the compound combined the notion of 'death' + 'a keeping watch'.

Initially it referred chiefly to a vigil kept beside the dying; later the name was also applied to the ticking wood‑boring beetle whose sound was superstitionally associated with impending death, and the figurative sense (a waiting for an end) developed.