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yellow alert

American  

noun

  1. (in military or civilian defense) the first alert given when enemy aircraft are discovered approaching a military installation, city, coastline, etc.

  2. the signal or alarm sounded for this alert.

  3. any primary stage of alert, as when toxic chemicals have escaped in a particular area and a potential hazard exists.


Etymology

Origin of yellow alert

First recorded in 1965–70

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Heatwave conditions are expected to remain more widely in the north-west of England, East Midlands, east of England, London and the south-east, where a yellow alert is in effect for the same period.

From BBC Jul. 12, 2026

A yellow alert for snow and ice is in place for Counties Donegal, Cavan, Monaghan, Louth and Connacht.

From BBC Jan. 5, 2026

A yellow alert for County Donegal lasts from 20:00 local time on Friday until 11:00 on Saturday.

From BBC Jan. 3, 2026

An amber weather warning was in place in the Western Isles while the south of Scotland was covered by a yellow alert.

From BBC Dec. 10, 2025

Until further notice, we must proceed under a yellow alert during daylight hours and a red alert at night.

From The Test Colony by Winston K. Marks

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