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Neptune

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Etymology and origin of the English word Neptune

Confidence
Established
Formation
Borrowing
First attested
Old English translation of Apollonius of Tyre
Borrowed from
Latin Neptunus
Ultimate origin
Latin Neptūnus

Pronunciation

  • /ˈnɛptjuːn/, /ˈnɛpt͡ʃuːn/[1]

Etymology

It is borrowed from Latin Neptūnus, the Roman god of the sea, whose further origin the OED calls uncertain.[2][3] Klein and Etymonline take it as probably from an Indo-European base also found in nebula (“mist, fog, cloud”): Etymonline writes it Proto-Indo-European *nebh- (“cloud”), through a sense "moist, wet",[3][4] and Klein compares the Avestan word for "moist".[4] Partridge reports a comparison with Vedic and Avestan names meaning "descendant of the waters".[5] Compare Middle French Neptune, used of the sea from the 16th century and of the planet from 1848.[2]

Earliest recorded meaning

The god of the sea: in Old English, in the translation of Apollonius of Tyre;[2] Etymonline dates it to the late 14th century.[3]

Semantic evolution

Neptune was son of Saturn and brother of Jupiter, and was later identified with the Greek Poseidon.[3][4][6] The name could also stand for the sea itself, as in Shakespeare's Neptune's yellow sands.[7][2] From 1662 it named a brass or copper pan used to evaporate sea water for salt,[2] and Merriam-Webster records its use in trade with Africa.[7] From 1815 it was also the sailor who plays the god in the ceremony held on board ship at the equator.[2] The planet was found on the night of 23–24 September 1846 by Johann Gottfried Galle, using a position that Urbain Le Verrier had predicted from anomalies in the motion of Uranus, and Le Verrier named it.[3] Etymonline adds that observers with telescopes had seen it as far back as Galileo without recognising it as a planet, and that it has been the most distant known planet both before 1930 and again since the demotion of Pluto.[3]

Timeline

  • 1662 – a brass or copper pan for evaporating sea water.[2]
  • 1815 – a sailor impersonating the god when crossing the equator.[2]
  • 1847 – the planet, in the American Journal of Science.[2]

Meanings

Noun

  1. The eighth planet from the sun.[2][6][7]
  2. In Roman mythology, the god of the sea, corresponding to the Greek Poseidon; poetically, the sea.[2][7][6]
  3. A sailor playing the god in a ceremony held on board ship when crossing the equator.[2]
  4. A brass or copper pan formerly used for evaporating sea water, or in trade with Africa; now historical.[2][7]

Word family

  • Neptunian
  • neptunium

References

  1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  4. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  5. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
  6. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
  7. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster

Related etymologies

Cite this entry

“Neptune.” Etymologically, 6 Nov. 2026, etymologically.com/en/Neptune. Accessed 6 Nov. 2026.

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