warning signal

Từ điển WordNet v3.1 - WordNet Dictionary

noun

an automatic signal (usually a sound) warning of danger
• Syn:
alarm, alert, alarum
• Derivationally related forms:
alert (for: alert)
• Hypernyms:
signal, signaling, sign
• Hyponyms:
torpedo, air alert, burglar alarm, fire alarm, foghorn,
fogsignal, horn, red flag, siren, tocsin, alarm bell