the.com/welding torch

means A handheld tool that mixes gas (or uses electricity) to produce a precisely controlled flame or arc hot enough to melt and fuse metal.

from 'Weld' comes from the Middle English 'wellen,' meaning to boil or well up — a fitting image, since early welding really was a kind of controlled boiling of metal until it fused. 'Torch' traces back through Old French 'torche' to Vulgar Latin 'torca,' related to 'torquere,' to twist — the earliest torches were twisted bundles of fiber soaked in pitch. The welding torch itself is a much younger invention: oxy-fuel and electric arc welding tools emerged in the late 19th and early 20th centuries, marrying that ancient word for a twisted flaming stick to industrial-age chemistry and metallurgy.