Torpedo
early 16th century (in torpedo (sense 2 of the noun)): from Latin, literally ‘stiffness, numbness’, by extension ‘electric ray’ (which gives a shock causing numbness), from torpere ‘be numb or sluggish’. torpedo (sense 1 of the noun) dates from the late 18th century and first described a timed explosive device for detonation under water.
wiktionary
Borrowed from Latin torpēdō(“a torpedo fish; numbness, torpidity, electric ray”), from torpeō(“I am stiff, numb, torpid; I am astounded; I am inactive”) + -ēdō(noun suffix), from Proto-Indo-European *ster-(“stiff”).
Cognate with Old English steorfan(“to die”), Ancient Greek στερεός(stereós, “solid”), Lithuanian tirpstu(“to become rigid”), Old Church Slavonic трупети(trupeti).
etymonline
torpedo (n.)
1520s, "electric ray" (flat fish that produces an electric charge to stun prey or for defense), from Latin torpedo "electric ray," originally "numbness, sluggishness" (the fish so called from the effect of being jolted by the ray's electric discharges), from torpere "be numb" (from PIE root *ster- (1) "stiff"). The sense of "explosive device used to blow up enemy ships" is first recorded 1776, as a floating mine; the self-propelled version is from c. 1900. Related: Torpedic.
Torpedo. A fish which while alive, if touched even with a long stick, benumbs the hand that so touches it, but when dead is eaten safely. [Johnson]
torpedo (v.)
"destroy or sink (a ship) by a torpedo," 1874, from torpedo (n.). Also used late 19c. of blowing open oil wells. Figurative sense attested from 1895. Related: Torpedoed; torpedoing.
