Brit a small portable electric lamp powered by batteries
esp formerly, a burning stick of resinous wood or twist of tow used to give light
a gas-burning implement providing a hot flame, esp for welding
something, e.g. wisdom or knowledge, that gives enlightenment or guidance
carry a torch for
to be in love with (somebody who does not return one's love)
put to the torch/put a torch to
to destroy (something) by burning it
[Middle English from Old French torche twist of material for burning, ultimately from Latin torques: see torc]