Origins
Every rocket launch re-enacts, in etymology, the throwing of a spear.βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ The word comes from Old French lanchier, meaning 'to fling, to hurl', from Late Latin lanceΔre β 'to wield a lance'. The original launch was a thrown weapon.
Latin lancea is itself a borrowing, probably from a Celtic or Iberian language. Roman writers noted that the lancea was not native to Latin military vocabulary but adopted from the peoples they conquered in Hispania. The spear came first; the Latin word followed.
The nautical sense β launching a ship β appeared by the 15th century. Pushing a vessel down the slipway into water carried the same energy as hurling a lance: a forceful, directed, irreversible sending-forth. Once launched, you cannot easily call it back.
Later History
The family tree includes lance (the weapon itself), lancer (a cavalryman armed with one), lancet (a small surgical blade shaped like a lance-tip), and freelance. The freelance is the most colourful relative: medieval mercenaries whose lances were 'free' β not sworn to any particular lord. Sir Walter Scott popularised the term in Ivanhoe (1820), though the concept was centuries older.
Modern English has pushed launch far from its martial origins. We launch products, campaigns, investigations, and careers. But the violence of the original throw lingers in the word's energy: a launch is never gentle.