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Latin Grammar I, Lesson 14. Of the Genitive Case of the Third Declension (of Nouns)

In lesson 13, we learned of the third declension of Latin nouns. Unlike first and second declension nouns, third declension nouns have many different forms, which can cause confusion. In this lesson, we will learn the various ways that third declension nouns form their genitive cases, which will bring some order to these nouns.

To complete the objectives of this lesson, complete the following tasks:

  1. Read over the entire lesson once for familiarity.
  2. Study the translation of each rule in the lesson.
  3. Note the different Nominative endings by which third declension nouns are divided.
  4. Learn the general and special ways in which genitive cases are formed for each group of third declension nouns.
  5. Study the lesson for mastery.
  6. Complete the lesson assessment.

If you need any help with this lesson, please post your questions on the course Student Forum in the Study Center.

Lesson

I. Neutra in E mutant ipsum E nominativi in IS, ut: omne, omnis; cubile, cubilis.

Translation: Neuter (nouns of the third declension that end) in E change that E of the Nominative (case) into IS (to make the Genitive case), as: omne (becomes) omnis; cubile (becomes) cubilis.

II. O finita ONIS accipiunt in genitivo: ut harpago, harpagonis. Verum caro habet carnis, Nerio et Anio, Nerienis, Anienis. Praeterea foeminina in DO, GO (excepto unedo, unedonis) faciunt INIS, ut: grando, grandinis; siligo, siliginis. His adde masculina Apollo, ordo, margo, cardo, cupido, homo, nemo, turbo.

Translation: (Nouns of the third declension) with O ended take ONIS in (the) Genitive (case), as: harpago, harpagonis. But (the noun) caro has carnis, Nerio and Anio (have) Nerienis (and) Anienis. Besides (these) feminine (nouns that end) in DO (and) GO (except unedo, unedonis) make INIS, as: grando, grandinis; siligo, siliginis. To these add (the) masculine (nouns) Apollo, ordo, margo, cardo, cupido, homo, nemo, turbo.

III. L, D, T, finita addunt IS genitivo, ut: vigil, vigilis; David, Davidis; caput, capitis verso U in I, ut etiam in ejus compositis. At mel et fel, mellis et fellis habent altero L adhibito in obliquis.

Translation: (Third declension nouns with the letters) L, D and T ended add IS in the genitive (case), as: vigil, vigilis; David, Davidis; (the noun) caput (makes) capitis (in the genitive case) verso U in I, ut etiam in ejus compositis. At mel et fel, mellis et fellis habent altero L adhibito in obliquis.

IV. N terminata IS genitivo superaddunt. At neutra N finita et composita a verbo cano INIS in genitivo sibi vindicant, ut: abdomen, abdominis; carmen, carminis. tibicen, tibicinis; tubicen, tubicinis; cornicen, cornicinis; quibus adde flamen, flaminis; pecten, pectinis.

Translation: (Third declension nouns with the letter) N terminated add IS in the Genitive (case). But neuter (nouns with the letter) N ended, and (nouns) composed from (the) verb cano, claim for themselves (the ending) INIS in (the) Genitive (case), as: abdomen, abdominis; carmen, carminis; tibicen, tibicinis; cornicen, cornicinis; to which add flamen, flaminis; pecten, pectinis.

V. Terminata in R addita syllaba IS formant genitivum, ut: lar, laris; acer, aceris; ver, veris; Mulciber, Mulciberis; Gadir, Gadiris, Anxur, Anxuris. Multa nomina syllaba ER finita amittunt E nominativi. Eiusmodi sunt: I. adjectiva in CER, ut acer, alacer, volucer. II. Nomina in TER, ut accipiter, accipitris; praeter later, lateris; iter, itineris. III. Nomina mensium, ut: September, Septembris; et certa nomina, ut imber. Verum ebur, femur, robur, jecur gignunt eboris, femoris, roboris, jecoris, jecinoris, et jocinoris; cor et far, cordis, farris.

Translation: (Third declension nouns) terminated in R form (the) Genitive (Case) with the syllable IS added, as: lar, laris; acer, aceris; ver, veris; Mulciber, Mulciberis; Gadir, Gadiris; Anxur, Anxuris. Many nouns with (the) syllable ER ended drop (the) E of (the) Nominative (case). Of this kind are: I. Adjective (nouns that end) in CER, as acer, alacer, volucer. II. Nouns (ending) in TER, as accipiter, accipitris; besides later, lateris; iter, itineris. III. Names of (the) months, as: September, Septembris; and certain other nouns, as imber. But ebur, femur, robur, jecur produce (the Genitive cases) eboris, femoris, roboris, jecoris, jecinoris, and jocinoris; cor and far (produce) cordis and farris.

VI. AS vertitur in ATIS, ut: honestas, honestatis; Maecenas, Maecenatis; arpinas, arpinatis. Vas tamen masculinum habet vadis; neutrum vasis; anas, anatis; mas, maris; as, assis.

Translation: (The Nominative ending) AS is changed into (the Genitive ending) ATIS, as: honestas, honestatis; Maecenas, Maecenatis; arpinas, arpinatis. (The noun) vas nevertheless (being) masculine has (for its Genitive case) vadis; (being) neuter (has) vasis; (the noun) anas (has) anatis; mas, (has) maris; (and) as (has) assis.

VII. ES habet genitivum in IS, aequalem nominativo, ut fames, famis; vepres, vepris; acinaces, acinacis. ES vertunt in ETIS aries, abies, interpres, seges, praepes, paries, indiges, perpes, teges, arietis, tegetis, et sic in aliis. Quies habet quietis; requies, requietis et requieii, sed tunc ad quintam declinationem spectat. Cetera appellativa latina praeter jam enumerata, sive masculina, sive communia tam duorum, quam trium generum, ITIS habent in genitivo. Masculina, ut Cocles, eques, gurges, fomes, limes, pedes, poples, stipes, termes, trames, veles. Communia duorum, ut antistes, comes, hospes, miles, satelles. Trium generum, ut ales, dives, sospes, ac superstes. His addantur ames, merges, tudes, licet foeminina. Genitivus in EDIS fit a nominibus merces, praes, haeres; a pes, pedis. Composita vero a verbo sedeo IDIS habent in genitivo, ut deses, desidis; praeses, praesidis; reses, residis.

Translation: (Third declension nouns that end in) ES have the Genitive (case) in IS, equal (in number of syllables) with (the) Nominative (case), as: fames, famis; vepres, vepris; acinaces, acinacis. (The Nominative ending) ES (they) change into ETIS (in the Genitive case) (the nouns) aries, abies, interpres, seges, praepes, paries, indiges, perpes, teges, arietis, tegetis, and so in others. (The nouns) Quies has quietis (in the Genitive case); requies (has) requietis and requieii, but then looks to the fifth declension (rather than the third). (The) other appellative Latin (nouns) besides (those) already enumerated, either masculine, or as common of two, or as of three genders, have (the ending) ITIS in (the) Genitive (case). Masculine (nouns), as Cocles, eques, gurges, fomes, limes, pedes, poples, stipes, termes, trames, veles. Common of Two, as antistes, comes, hospes, miles, satelles. Common of Three genders, as: ales, dives, sospes, ac superstes. To these are added ames, merges, tudes, if (they are) feminine (in gender). (The) Genitive (case) in EDIS is made by the nouns merces, praes, haeres; from pes (is made) pedis. And (Nouns that are) composed from the verb sedeo have (the ending) IDIS in (the) Genitive (case), as deses, desidis; praeses, praesidis; reses, residis.

VIII. IS finita genitivum faciunt similem nominativo, ut facilis, facilis. At a vomis, pulvis, cinis, cucumi, fiunt genitivi vomeris, pulveris, cineris, cucumeris, et cucumis sine incremento; a Quiris, Samnis, dis, lis fiunt Quiritis, Samnitis, ditis, litis; a vis plurali numero vires, virium, viribus.

Translation: (Third declension nouns with the ending) IS ended make (the) genitive (case) like to the Nominative, as: facilis, facilis. But from (the nouns) vomis, pulvis, cinis, cucumi, are made the Genitives vomeris, pulveris, cineris, cucumeris, and cucumis without increase (in the number of sullables); from (the nouns) Quiris, Samnis, dis (and) lis are made (the Genitive cases) Quiritis, Samnitis, ditis (and) litis; from vis in the plural number is made vires, virium, viribus.

IX. OS modo vertitur in ŌTIS, ut dos, dotis; cos, cotis; sacerdos, sacerdotis; modo in ŎTIS, ut impos, impotis; compos, compotis; modo in ODIS, ut custos, custodis; alias in ORIS, ut ros, roris; flos, floris; mos, moris, glos, gloris; et nomina in OS vel OR desinentia, ut arbos vel arbor , honos vel honor, lepos vel lepor. OS sub diversis significationibus gignit oris et ossis. Bos habet boves sed in genitivo plurali boum, in dativo et ablativo bobus vel bubus.

Translation: (Third declension nouns whose Nominative ends in) OS in a way are changed (in the Genitive case) into ŌTIS (with a long O), as dos, dotis; cos, cotis; sacerdos, sacerdotis; in a way into ŎTIS (with a short O), as impos, impotis; compos, compotis; in a way into ODIS, as custos, custodis; others into ORIS, as ros, roris; flos, floris; mos, moris, glos, gloris; and nouns ending in OS or OR, as arbos or arbor, honos or honor, lepos or lepor. The noun os under different significations produces (the Genitive cases) oris (mouth) and ossis (bone). (The noun) bos has boves but in (the) Genitive plural has boum, in the dative and ablative bobus or bubus.

X. US nominativi quaedam nomina vertunt in ŎRIS, ut corpus, decus, dedecus; facinus, fænus, frigus, lepus, litus, nemus, pignus, tergus, pecus ac penus neutro genere; nam foeminino pecus habet pecudis; penus vero ad quartam vel secundum declinationem spectat. Comparativa neutra in ŌRIS, ut majus, minus, pejus, majoris, minoris, pejoris. Alia mutant in ERIS, ut scelus, sidus, glomus, viscus, acus, aceris neutrum. Masculinum enim acus, aci ad secundum declinationem; foemininum acus ad quartam, idque sub diversis significationibus, spectat. Monosyllaba US vertunt in URIS, ut crus, jus, mus, rus, pus quibus adde tellus, telluris. At sus habet suis; juventus, salus, servitus, senectus, virtus et cetera foeminina US mutant in UTIS praeter palus et sub scus, quae US vertunt in UDIS.

Translation: Certain nouns change (the) US of (the) Nominiative into ŎRIS (in the Genitive case), as: corpus, decus, dedecus; facinus, fænus, frigus, lepus, litus, nemus, pignus, tergus, pecus or penus in (the) neuter gender; for in the feminine pecus has pecudis (in the Genitive case); penus however to the fourth or second declension looks. Neuter comparative (nouns) (make the Genitive case) in ŌRIS, as: majus, minus, pejus, majoris, minoris, pejoris. Others change into ERIS, as: scelus, sidus, glomus, viscus, acus, aceris (when) neuter. For (when) masculine acus, aci to (the) second declension; (when) feminine acus to (the) fourth, and that under diverse significations looks. Monosyllabic (nouns ending in) US change (their ending) into URIS, as: crus, jus, mus, rus, pus to whcih add tellus, telluris. At sus habet suis; juventus, salus, servitus, senectus, virtus et cetera foeminina US mutant in UTIS praeter palus et sub scus, quae US vertunt in UDIS.

XI. Nomina literis BS vel PS finita formant genitivum. I vocali medio utriusque consonantis interposita, ut stirps, stirpis; urbs, urbis; inops, inopis. Polysyllaba vero vocalem E duas illas consonantes praeeuntem in I mutant in genitivo, ut caelebs, caelibis; forceps, forcipis; sic manceps, municeps, particeps, et similia. At anceps, biceps, triceps gignunt ancipitis, bicipitis; auceps, aucupis.

Translation: Nouns ended with the letters BS or PS form (the) Genitive (case) (with the) vowel I interposed between each of (these) consonants, as: stirps, stirpis; urbs, urbis; inops, inopis. Polysyllabic (nouns) however change (the) vowel E going before those two consonants into I in (the) Genitive (case), as: caelebs, caelibis; forceps, forcipis; likewise manceps, municeps, particeps, and (those) similar. But anceps, biceps, triceps produce ancipitis, bicipitis; auceps, aucupis.

XII. Finita in NS vel RS vertunt S in TIS, ut fons, fontis; tiburs, tiburtis. Lens et frons habent lentis et lendis; frontis et frondis sed alia significatione. Anomala sunt iens, euntis et composita abiens, exiens, etc.; et derivata a cor, cordis; quae retinent DIS a simplici ut concors, concordis; itemque libripens, libripendis a pendo et libra compositum.

Translation: (Third declension nouns) ended in NS or RS change (the) S into TIS (in the Genitive case), as: fons (becomes) fontis; tiburs, tiburtis. Lens et frons have (the Genitive cases) lentis and lendis; frontis and frondis but with another signification. Irregular (nouns) are iens (which makes) euntis and (their) compound (nouns) abiens, exiens, etc.; and (nouns) derived from cor, cordis; which retain (the) DIS from (the) simple (noun) as: concors, concordis; and also libripens, libripendis composed from pendo and libra.

XIII. X vertitur in CIS, ut: Ajax, Ajacis; cornix, cornicis; volvox, volvocis; Pollux, Pallucis. Aliquando tamen in GIS, ut grex, gregis; Lelex, Lelegis; aquilex, aquilegis; frux, frugis; remex, remigis; conjux, conjugis; rex, regis; Biturix, Biturigis; lex, legis. His adde Orgentarix, Orgentorigis; Vercingetorix, Vercingetorigis; et similia quaedam nomina in ORIX. Polysyllaba E nominativi praecedens mutant in I, ut: codex, codicis; vertex, verticis; vibex, vibicis. Excipiuntur vervex, vervecis; resex, resecis. Anomala sunt nix, nivis; nox, noctis. Reliqua usu disces.

Translation: (Third declension nouns have the ending) X changed into CIS, as: Ajax, Ajacis; cornix, cornicis; volvox, volvocis; Pollux, Pallucis. For some, however, X (is changed) into GIS, as: grex, gregis; Lelex, Lelegis; aquilex, aquilegis; frux, frugis; remex, remigis; conjux, conjugis; rex, regis; Biturix, Biturigis; lex, legis. To these add Orgentorix, Orgentorigis; Vercingetorix, Vercingetorigis; and certain similar nouns (that end) in ORIX. Polysyllabic (nouns) change the preceding E of (the) nominative into I, as: codex (becomes) codicis; vertex, verticis; vibex, vibicis. (The nouns) vervex, vervecis; (and) resex, resecis are excepted. (The nouns) nix, nivis; (and) nox, noctis are irregular. (The) you shall learn by use.

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