Definition of "tripwire" [tripwire]

• A wire stretched near ground level to trip or ensnare an enemy. (noun)
• A wire or line that activates a weapon, trap, or camera, for example, when pulled. (noun)
• A small military force whose involvement in hostilities will trigger the use of a larger force. (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.

• "The 82nd was variously called a tripwire, or, more cynically, a "speed bump", as a paratroop division could not have directly fought Iraqi armored units."
• "No mention that the "tripwire" came when Limbaugh said he hoped Obama fails, four days before Obama was inaugurated."
• "The GIs understood their role: If the North Koreans ever came south again, they would be the tripwire Washington would need to intervene and send for help--"tripwire" being a term Gen. LaPorte rejected when I asked him to describe their role."