Etymologically

Etymology and origin of the Latin word ob-

Confidence
Established
Formation
Inherited
Inherited from
Proto-Italic *op(i)
Ultimate origin
Proto-Italic *op(i)

Forms

ob- [1] ob- before vowels, ⟨s⟩, ⟨t⟩, ⟨h⟩ and voiced consonants other than ⟨g⟩;[2][3] oc- before ⟨c⟩, of- before ⟨f⟩, og- before ⟨g⟩, op- before ⟨p⟩; before ⟨m⟩ obm- or om-.[2][3] The original op- survives in opācus, operiō and oportet, and an extended o(p)s- in oscen and ostendō.[3][2]

Etymology

It is the preposition ob (“towards; against”) used as a prefix,[1] inherited from Proto-Italic *op(i).[2] De Vaan takes it, with Lithuanian ap(i)- (“around”), as a reflex of Proto-Indo-European *h₁opi (“at, by”), an ablaut variant of the Proto-Indo-European *h₁epi seen in Sanskrit अपि (ápi) and Ancient Greek ἐπί (epí, “on, at”).[2] Italic cognates are Oscan úp (“at”) and Faliscan opidque (“and on account of that”).[2] He notes that ⟨obs-⟩ is a recent, short-lived variant, while ⟨os-⟩ in ostendō is older.[2]

Semantic evolution

In compounds it usually expresses opposition or confrontation, or a movement towards something.[3][1]

Meanings

Prefix

  1. Towards, to meet, in the way of: occurrō, offerō.[1][3]
  2. Against, in opposition: obstō, oppugnō, oppōnō.[3][1]

Word family

References

  1. ^ a b c d e Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
  3. ^ a b c d e f Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press

Derived terms

Descendants

Related etymologies

  • -ce · also from Proto-Italic
  • -que · also from Proto-Italic
  • per- · also from Proto-Italic
  • pro- · also from Proto-Italic
  • prae- · also from Proto-Italic
  • trans- · also from Proto-Italic
  • bi- · also from Proto-Italic
  • tri- · also from Proto-Italic
Cite this entry

“Ob-.” Etymologically, 23 Oct. 2026, etymologically.com/la/ob-. Accessed 23 Oct. 2026.

Last edited on . ·