Meaning: A warning of imminent danger or emergency.

Part of speech: noun

Example: The city was placed on red alert due to the storm.

Category: Emergency

Synonyms:

• emergency alert
• warning

Meaning: A distress signal used internationally, often in emergencies.

Part of speech: noun

Example: They sent an SOS when their boat capsized.

Category: Emergency

Synonyms:

• distress signal
• emergency call