Tripwire
Full definition of tripwire
Noun
tripwire
(plural tripwires)- A cord or wire arranged so that when snagged or pulled by an intruder, it will trigger a detector or trap or a device, such as a land mine.
- Seeing the tripwire of a nearby bouncing Betty gave us cold chills, and we moved all the more slowly through the woods.
- Any means of detecting intruders.