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
- Towards, to meet, in the way of: occurrō, offerō.[1][3]
- Against, in opposition: obstō, oppugnō, oppōnō.[3][1]
Word family
Related words
References
- ^ a b c d e Wiktionary, the free dictionary, https://en.wiktionary.org
- ^ 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
- ^ a b c d e f Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
Derived terms
- obduro
- obeo
- obequito
- oberro
- obiaceo
- obirascor
- obiurgo
- oblecto
- oblino
- obloquor
- obluctor
- obmoveo
- obmutesco
- obnitor
- obnuntio
- oborior
- obrepo
- obrigesco
- obruo
- obsaepio
- obscurus
- obsecro
- obsero
- obsido
- obsolesco
- obsono
- obstrepo
- obstupefacio
- obstupesco
- obtego
- obtempero
- obtendo
- obtero
- obtingo
- obtorqueo
- obtrecto
- obtrunco
- obtundo
- obturbo
- obumbro
- obversor
- obverto
- obvolvo
- occaeco
- occipio
- occubo
- occulo
- occumbo
- offendix
- officio
- offirmo
- offundo
- omitto
- oppeto
- opprimo
- oppugno
Descendants
- English oblivion
Related etymologies
Cite this entry
“Ob-.” Etymologically, 23 Oct. 2026, etymologically.com/la/ob-. Accessed 23 Oct. 2026.
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