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certo

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Etymology and origin of the Latin word certo

certo1 contend

Confidence
Established
Formation
Derivation
First attested
c. 250–184 BC, Plautus
Ultimate origin
Proto-Indo-European (*krey-)
Etymology tree of certo1
inherited borrowed derived
Latin cerno
Latin incerno
Latin crimen
French crime
Latin criminalis
English criminal
Latin certo
Latin discerno

Pronunciation

  • Classical: [ˈkɛr.toː][1]
  • Ecclesiastical: [ˈt͡ʃɛr.to][1]

Forms

certō (present infinitive certāre, perfect active certāvī, supine certātum); first conjugation[1]

Etymology

The verb “to contend” is formed from Latin cernō (“to sift, decide”) + -tō, a frequentative built on the old participle certus (“decided”).[2][3][1] L&S take the first sense to be “to decide something by a contest”.[3] De Vaan derives cernō from Proto-Italic *krin-e/o- and its old participle from Proto-Italic *kritos, from Proto-Indo-European *krey- (“to sift, separate”).[4]

Earliest recorded meaning

Plautus has it of rivalry: stultus atque īnsānus damnīs certant, “the fool and the madman vie in losses”.[2] Ennius uses it of battle and of rivalry: certābant urbem Rōmam Remoramne vocārent, “they disputed whether to call the city Rome or Remora”.[2]

Semantic evolution

Certāre is to contend for superiority, “to vie, compete” (Cicero: ut ūtilitās cum honestāte certet, “that advantage should vie with honour”), to fight in battle, and in the passive to be fought over (Ovid).[2][3] It is used of contests in sport, of disputes in argument, of lawsuits (Cicero: dē spōnsiōne certāret, “should go to law about the wager”) and of political struggles.[2][1] L&S stress that it implies great exertion and a measuring of strength.[3]

Church Latin glosses it “to fight, contend, struggle”.[5]

Timeline

  • c. 250–184 BC – Plautus: damnīs certant.[2][6]
  • 204–169 BC – Ennius uses it of battle and of the naming of Rome.[2][6]
  • 81–43 BC – Cicero uses it of rivalry and of lawsuits.[2][6]

Meanings

Verb

  1. To contend, vie (for superiority), emulate.[2][3][1]
  2. To fight (in battle);[2][1][5] (passive) to be fought over.[2]
  3. To compete (in a sporting or other contest).[2][1]
  4. To dispute, argue.[2][1]
  5. To contend at law;[2][1] to contest (a matter).[2]
  6. To engage in political struggle.[2]
  7. To strive, try hard (with an infinitive).[1]

Word family

  • certāmen
  • certātim
  • certātiō
  • certātor
  • concertō
  • dēcertō

certo2 certainly

Confidence
Established
Formation
Derivation
First attested
c. 250–184 BC, Plautus
Ultimate origin
Proto-Indo-European (*krey-)
Etymology tree of certo2
inherited borrowed derived
Latin certus
Latin certe
Latin incertus
Latin certo

Pronunciation

  • Classical: [ˈkɛr.toː][1]
  • Ecclesiastical: [ˈt͡ʃɛr.to][1]

Forms

certō (comparative certius, superlative certissimē)[1]

Etymology

The adverb “certainly” is formed from Latin certus (“sure, certain”) + -ō, an adverb in ⟨-ō⟩ beside certē.[2][1] certus is the old past participle of cernō (“to sift, decide”), from Proto-Italic *kritos, from Proto-Indo-European *kri-to- and *krey- (“to sift, separate”).[4]

Earliest recorded meaning

Plautus has mihi certō nōmen Sōsiaest, “my name is certainly Sosia”, and uses it alone in answers, “certainly”.[2][6] Köbler first records it from Terence.[6]

Semantic evolution

Certō is “certainly, for a fact”, often as an answer (Plautus: esne tū Syrācūsānus? – certō).[2][1] With sciō it means “to know for certain”, the commonest use.[2] It also means “firmly, dependably” (ūnum quidem hercle certō prōmittō tibi, “one thing I promise you for sure”), and the comparative certius is “more definitely” (Cicero: dē Curtiō ad mē rescrībe certius, “write back to me more definitely about Curtius”).[2]

Timeline

  • c. 250–184 BC – Plautus: mihi certō nōmen Sōsiaest.[2][6]
  • 190–159 BC – Terence uses it.[6]
  • 81–43 BC – Cicero uses the comparative certius.[2][6]

Meanings

Adverb

  1. certainly, for a fact;[2][1] certainly! (in answers).[2]
  2. certō sciō: to know for certain.[2]
  3. Firmly, surely, dependably.[2][1]
  4. (comparative certius) More definitely.[2]

References

  1. ^ a b c d e f g h i j k l m n o p q r Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 28 Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d e Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  4. ^ a b de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
  5. ^ a b Stelten, Leo F. (1995), Dictionary of Ecclesiastical Latin, Peabody, Mass.: Hendrickson
  6. ^ a b c d e f g h Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de

Derived terms

Cite this entry

“Certo.” Etymologically, 18 Oct. 2026, etymologically.com/la/certo. Accessed 19 Oct. 2026.

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