Meanings
alternative 0-dark-thirty · alternative oh-dark-thirty · alternative zero dark thirty · alternative dark thirty
- idiomaticSome unspecified hour in the early morning (implying an unpleasant time to be awake).
I had to get up at oh dark thirty to catch a plane.
Synonyms: crack of dawn, dark o’clock, stupid o'clock, wee small hours
Synonyms & antonyms
nounSome unspecified hour in the early morning (implying an unpleasant time to be awake).
Origin
From U.S. military terminology, in which hours before 10:00 am are prefixed with a zero, read as "oh", as in 0530, oh five-thirty, for 5:30 am.
Full word history & related roots →Cite this entry
oh dark thirty. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/oh%20dark%20thirty
“oh dark thirty.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/oh%20dark%20thirty. Accessed November 5, 2026.
WatkinsX Dictionary, s.v. “oh dark thirty,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/oh%20dark%20thirty.
Source: oh dark thirty on Wiktionary, CC BY-SA 4.0.