zero hour
Advanced (C1) formal
The critical moment when something important is about to happen.
"As zero hour approached, the entire team held their breath."
Hear it in context
A Journey Through History With Comedy Legends | Our DNA Journey | Ancestry®
Ancestry · 19:46
point, they were all on zero hour
The Amchitka Nuclear Tests - How Modern Environmentalism Was Born
The Cold War · 9:31
Just hours before zero hour, the justices declined