heliosheath

H4E1L1I1O1S1H4E1A1T1H4

noun

A zone between the termination shock and the heliopause, in the heliosphere, at the outer border of the Solar System, where the solar wind is dramatically slower than within the termination shock.

OriginEnglish sheath ← Ancient Greek ἥλῐος (hḗlĭos) ← Proto-Hellenic *hāwélios →
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Meanings

nounheliosheath (plural heliosheaths)

plural heliosheaths

  1. astronomyA zone between the termination shock and the heliopause, in the heliosphere, at the outer border of the Solar System, where the solar wind is dramatically slower than within the termination shock.

    We encroach deeper into the furthest extent of the heliosheath, which thins out all the time.

    2023, Martin MacInnes, In Ascension, Atlantic Books, page 388

Origin

  1. Proto-Indo-European*sóh₂wl̥
  2. Proto-Indo-European*sh₂wél(i)yos
  3. Proto-Hellenic*hāwélios
  4. Ancient Greekἥλῐος (hḗlĭos)
  5. Englishhelio-
  6. Englishsheath
  7. Englishheliosheath

From helio- + sheath.

Full word history & related roots →

Translations

Finnish heliovaippa
  • heliovaippazone between the termination shock and the heliopause
French héliogaine
  • héliogainezone between the termination shock and the heliopause
Polish płaszcz Układu Słonecznego
  • płaszcz Układu Słonecznegozone between the termination shock and the heliopause
Cite this entry
APA

heliosheath. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/heliosheath

MLA

“heliosheath.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/heliosheath. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “heliosheath,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/heliosheath.

Source: heliosheath on Wiktionary, CC BY-SA 4.0.