Definition

Noun 1. A warning signal indicating the start of a period of preparation for an enemy air attack. 2. A state of readiness in which combat aircraft are airborne and prepared for a mission. 3. The time period during which military and civilian agencies are prepared for a potential enemy air attack.

Usage Examples

• The sirens sounded, signaling an air alert, and everyone hurried to the shelters.
• Fighter jets were placed on air alert to patrol the border region.
• The country was under an air alert for 48 hours following the escalation of tensions.

Advanced Usage

• To be on (an) air alert: To be in a state of readiness for an air attack.
  • All defense units were placed on a heightened air alert.
• To go on air alert: To enter a state of readiness.
  • The base will go on air alert at dawn.

Variants and Related Words

• Alert (noun/adj): A warning or a state of readiness. While "alert" is a broader term, "air alert" specifies the threat domain (air attack).
• Ground alert (noun): A state of readiness where aircraft and crews are prepared to take off within a very short time, but are not yet airborne. This contrasts with the airborne state of an "air alert."

Synonyms

• Air raid warning
• Combat air patrol (specifically for the airborne mission state)
• Warning condition

Notes on Different Meanings

The term "air alert" has a specific military context. Its meanings are sequential and related: 1. The initial signal (warning siren). 2. The resulting operational state (aircraft airborne). 3. The duration of the prepared period. The exact meaning is determined by the context in which it is used.

Noun

1. the warning signal that begins a period of preparation for an enemy air attack
2. the condition in which combat aircraft are airborne and ready for an operation
   • aircraft in the Mideast are on air alert
3. the time period during which military and civilian agencies are prepared for an enemy air attack