Definition of "alert" []

• Vigilantly attentive; watchful: alert to danger; an alert bank guard. See Synonyms at aware. (adjective)
• Mentally responsive and perceptive; quick. (adjective)
• Brisk or lively in action: the bird's alert hopping from branch to branch. (adjective)
• A signal that warns of attack or danger: Sirens sounded the alert for an air raid. (noun)
• A condition or period of heightened watchfulness or preparation for action: Nuclear-armed bombers were put on alert during the crisis. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "However, in this alert is an unusual warning about the state of Durango:"
• "A travel "alert" is less serious than a full "travel warning," which could have big implications."
• "An e-mail alert from the technical office went out to all House staff members notifying them of the problem."