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prosum

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Etymology and origin of the Latin word prosum

Confidence
Established
Formation
Derivation
First attested
204–169 BC, Ennius
Ultimate origin
Proto-Indo-European (*h₁es-)
Etymology tree
inherited borrowed derived
Latin sum
French soit
Latin adsum
Latin absum
Latin prosum
Latin possum
Latin possibilis
English possible
French possible
Latin impossibilis
English impossible
French impossible
Latin intersum
Latin insum
Latin supersum
Latin desum

Pronunciation

  • Classical: [ˈproː.sũː][1]
  • Ecclesiastical: [ˈprɔː.s̬um][1]

Forms

prōsum (present infinitive prōdesse, perfect active prōfuī, future active participle prōfutūrus); irregular conjugation, suppletive, no passive, no supine stem except in the future active participle, no gerund[1] A future prōde erit is found in the land surveyor Agennius.[2]

Etymology

It is formed from Latin prō- + sum (“to be”).[2][3][1] Forms such as ⟨prōdesse⟩ show the variant ⟨prōd-⟩ of the prefix, which de Vaan takes to be a newer form built after ⟨red-⟩; he traces sum to Proto-Indo-European *h₁es- (“to be”).[4]

Earliest recorded meaning

Ennius has the line quī ipse sibi sapiēns prōdesse nōn quit, nēquīquam sapit, “a wise man who cannot help himself is wise in vain”.[2][3]

Semantic evolution

It is used of people “to be of use, help” and of things “to be helpful, beneficial”, with the dative of the person helped.[2][3] Cato uses it of remedies, “to be good for”, and the jurists of what tells in someone's favour.[2] Church Latin glosses it “to be profitable, useful”.[5]

The subjunctive prōsit “may it benefit (you)” became a toast, famous among German students, recorded in English from 1846.[6]

Timeline

  • 204–169 BC – Ennius: quī ipse sibi sapiēns prōdesse nōn quit.[2][7]
  • 230/220–168 BC – Caecilius: serit arborēs, quae saeclō prōsint alterī, “he plants trees to benefit another generation”.[2][7]
  • 234–149 BC – Cato prescribes a cup on an empty stomach: prōderit, “it will do good”.[2][7]
  • 1846 – Prosit recorded as a toast in English.[6]

Meanings

Verb

  1. To be of use, do good, help, benefit (with the dative).[2][3][1][5]
  2. To be beneficial, advantageous (of things).[2]
  3. To be good for (an illness).[2][1]
  4. (with ad) To tell in one's favour.[2]

Word family

  • prōde

Usage notes

A rare adverb prōsum is a form of prōrsum “straight on”; the OLD and the TLL list it separately.[2][8]

References

  1. ^ a b c d e f Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  4. ^ 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 Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  7. ^ a b c Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  8. ^ Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
Cite this entry

“Prosum.” Etymologically, 18 Oct. 2026, etymologically.com/la/prosum. Accessed 18 Oct. 2026.

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