A device used to detonate an explosive device etc.
a small explosive device attached to the railhead to provide an audible warning when a train passes over it.
A mine that is placed on land and designed to explode when stepped upon or touched.
A piece of exercise device consisting of a pivoting tube attached to the ground to which a barbell can be fitted to lift it off the ground.
A critical subject or situation with concealed or unpredictable implications.