Added 9 October 2026
deadline
/ˈdɛdˌlaɪn/ noun
noun Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about deadline at Wordnik → Where our words come from →
Origin
According to the Oxford English Dictionary, early usage refers to lines that do not move, such as one used in angling. Slightly later American usage refers to a boundary in a prison which prisoners must not cross. There is only indirect evidence that the sense of "due date" may be connected with this use of the term in prison camps during the American Civil War, when it referred to a physical line or boundary beyond which prisoners were shot.
From Wiktionary, via Kaikki.org (CC BY-SA)