"small automatic blast lamp, plumber's torch, apparatus in which a spray of gas is expelled in a very hot flame under air pressure," 1894, from blow (v.1) + torch (n.).
Entries linking to blow-torch
blow v.1
"move air, produce a current of air," Middle English blouen, from Old English blawan "to blow (of the wind, bellows, etc.), breathe, make an air current; kindle; inflate; sound" a wind instrument (class VII strong verb; past tense bleow, past participle blawen), from Proto-Germanic *blæ-anan (source of Old High German blaen, German blähen), from PIE root *bhle- "to blow."
The transitive sense of "carry by a wind or current of air" is from c. 1300; that of "fill with air, inflate" is from late 14c. Of noses, from 1530s; of electrical fuses, from 1902. The meaning "to squander" (money) is from 1874; that of "lose or bungle" (an opportunity, etc.) is by 1943. The sense of "depart (some place) suddenly" is from 1902.
As a colloquial imprecation by 1781, associated with sailors (as in Popeye's "well, blow me down!"); it has past participle blowed.
To blow (a candle, etc.) out "extinguish by a current of air" is from late 14c. To blow over "pass" is from 1610s, originally of storms. To blow hot and cold "vacillate" is from 1570s. To blow off steam (1837) is a figurative use from steam engines releasing pressure. Slang blow (someone or something) off "dismiss, ignore" is by 1986. To blow (someone's) mind was in use by 1967; there is a song title "Blow Your Mind" released in a 1965 Mirawood recording by a group called The Gas Company.
For the sexual sense, see blow-job.
torch n.
mid-13c., from Old French torche "torch," also "handful of straw" (for wiping or cleaning, hence French torcher "to wipe, wipe down"), originally "twisted thing," then "torch formed of twisted tow dipped in wax," probably from Vulgar Latin *torca, alteration of Late Latin torqua, from Latin torquere "to twist" (from PIE root *terkw- "to twist").
In Britain, also applied to the battery-driven version (in U.S., a flashlight). To pass the torch is an ancient metaphor from the Greek torch-races (lampadedromia) where the goal was to reach the finish line with the torch still burning. Torch-bearer "leader of a cause" is from 1530s. Torch song is 1927 ("My Melancholy Baby," performed by Tommy Lyman, is said to have been the first so called), from carry a torch "suffer an unrequited love" (also 1927), Broadway slang, but the sense is obscure.