trip wire, n.
a wire stretched close to the ground that activates something (a trap or camera or weapon) when tripped over
<noun.artifact>
trip wire
semantic pointers
hypernym
a small military force that serves as a first line of defense; if they become engaged in hostilities it will trigger the intervention of stronger military forces
<noun.group>
trip wire
semantic pointers
hypernym
domain of synset (topic)