What is Torching?

Torching definition and meaning on Dictionary terms:

a light to be carried in the hand, consisting of some combustible substance, as resinous wood, or of twisted flax or the like soaked with tallow or other flammable substance, ignited at the upper end.
something considered as a source of illumination, enlightenment, guidance, etc.: the torch of learning.
any of various lamplike devices that produce a hot flame and are used for soldering, burning off paint, etc.
Slang. an arsonist.
Chiefly British. flashlight(def 1).