transitive verb
1. : to describe or characterize to a nicety : hit off
a fine job of touching off the shallowness and confusion of his interloper role — Newsweek
2.
[ touch (as in touchhole )]
a. : to cause to explode by or as if by touching with fire
b. : to release or initiate with the sudden violence of an explosion
the charges touched off a storm of protest — R.A.Billington
3. : to start (a relay runner) by touching his extended hand