zero hour
/ˈziːroʊ ˈaʊər/
NOUN
1. The scheduled time for an important event to begin
The specific appointed time at which an event, operation, or planned activity is scheduled to start, especially a military operation.
1.1. Scheduled start of a military operation
The designated time at which a military operation, attack, or mission is ordered to commence, also known as H-hour.
Synonyms
- H-hour
- D-day
- appointed hour
- A-day
Examples
- The soldiers were briefed and prepared for the critical mission at zero hour.
- The commander gave the final instructions before zero hour arrived.
Related Words
- military operation
- deployment
- countdown
- mission
- invasion
- offensive
- mobilization
1.2. Appointed time for an event or activity
The predetermined moment when a scheduled event, launch, announcement, examination, or other important activity officially begins.
Synonyms
- appointed hour
- start time
- scheduled time
- launch time
- D-day
- H-hour
Examples
- The launch of the spacecraft was scheduled for zero hour, with everyone anxiously awaiting the countdown.
- The classroom fell silent as the exam papers were distributed, signaling that zero hour had arrived for the students.
Related Words
- deadline
- countdown
- commencement
- opening
- launch
- schedule
- milestone
1.3. Critical moment when action becomes necessary
The decisive or crucial moment when an important situation reaches its turning point and immediate action, a decision, or a response is required.
Synonyms
- moment of truth
- crunch time
- critical moment
- pivotal moment
- turning point
- crisis point
- decisive moment
Examples
- As the project deadline approached, the team worked tirelessly to meet the goals set for zero hour.
- The negotiations had reached zero hour, and both sides needed to make a final decision.
Related Words
- crisis
- crossroads
- conjuncture
- breaking point
- point of no return
- climax
- deadline