Lesson 39 · Review

The Third Declension: Consonant Stems — the genitive tells the truth

IVocabulary

Ten of these twelve words are third-declension nouns, and every one of them must be learned with its genitive attached — the nominative alone will not tell you how to decline it.

barbarus, -a, -umstrange, foreign; as a noun barbarī, savages
dux, ducism. leader (duke); cf. dūcō
eques, equitism. horseman, cavalryman (equestrian)
iūdex, iūdicism. judge
lapis, lapidism. stone (lapidary)
mīles, mīlitism. soldier (militia)
pedes, peditism. foot soldier (pedestrian)
pēs, pedism. foot (pedal)
prīnceps, prīncipism. chief (principal)
rēx, rēgism. king (regal)
summus, -a, -umhighest, greatest (summit)
virtūs, virtūtisf. manliness, courage (virtue)
Watch the pair — pēs and pedes

Two look-alikes that mean different things. Pēs, pedis is a foot; pedes, peditis is a foot soldier. And in pēs note the quantity: the e is long in the nominative singular but short in every other case — pēs, but pedis, pedem, pede.

IIBase and Stem

You have used the word "base" since the first declension. Now a second term is needed, because the third declension is named after something the first two are not.

WordBaseStemDeclension is named…
portaport-portā-Ā-Declension (first)
servusserv-servo-O-Declension (second)
mīlesmīlit-mīlit-Consonant Declension (third)
Rule 1 — Base plus stem vowel makes the stem

The base is the part of the word that does not change. Add to the base in the first declension, or -o in the second, and you get the stem. These two stem vowels matter so much to the case endings that the declensions are named after them.

porta — base port-, stem portā-; servus — base serv-, stem servo-.

Rule 2 — In consonant stems, base and stem are the same

The third declension is the Consonant or I-Declension, and its nouns are classified by how the stem ends. If the last letter of the stem is a consonant, the word has a consonant stem, and there the stem is the base — no vowel is added. If the stem ends in -i-, the word has an i-stem, formed by adding -i- to the base. That i changes certain cases, so the distinction is an important one.

This lesson covers consonant stems only. The i-stems come later.

Rule 3 — Two classes of consonant stem

Consonant stems fall into two classes: I. those that add -s to the base to form the nominative singular; II. those that add no termination at all in the nominative singular.

Every noun in this lesson belongs to Class I.

IIIThe Declension of Class I

Masculine and feminine nouns of Class I take one set of terminations. Learn the right-hand column and you can decline any of them.

prīnceps, m.
chief
mīles, m.
soldier
rēx, m.
king
virtūs, f.
courage
Terminations
M. and F.
Base / stemprīncip-mīlit-rēg-virtūt-
Nom. sg.prīncepsmīlesrēxvirtūs-s
Gen.prīncipismīlitisrēgisvirtūtis-is
Dat.prīncipīmīlitīrēgīvirtūtī
Acc.prīncipemmīlitemrēgemvirtūtem-em
Abl.prīncipemīliterēgevirtūte-e
Nom. pl.prīncipēsmīlitēsrēgēsvirtūtēs-ēs
Gen.prīncipummīlitumrēgumvirtūtum-um
Dat.prīncipibusmīlitibusrēgibusvirtūtibus-ibus
Acc.prīncipēsmīlitēsrēgēsvirtūtēs-ēs
Abl.prīncipibusmīlitibusrēgibusvirtūtibus-ibus
Rule 4 — Finding the base

The base — which in a consonant stem is also the stem — is found by dropping -is from the genitive singular. This is why the genitive is always given in the vocabulary: it, and not the nominative, is what shows you the word's real shape.

iūdicis-is = iūdic-; lapidis-is = lapid-; peditis-is = pedit-.

IVWhy the Nominative Looks Wrong

The genitive is regular; it is the nominative singular that hides things, and it hides them in exactly three ways.

Rule 5 — i in the base, e in the nominative

Most nouns of two syllables have i in the base but e in the nominative.

prīnceps (base prīncip-), mīles (base mīlit-), iūdex (base iūdic-). The word lapis is the exception — it keeps its i in the nominative too.

Rule 6 — A final -t or -d is dropped before -s

Latin will not tolerate -ts or -ds at the end of a word, so the consonant simply falls away when the nominative -s is added.

mīles stands for mīlets; lapis for lapids; virtūs for virtūts.

Rule 7 — A final -c or -g unites with -s to form -x

Here nothing is lost — the two consonants merge into a single letter, and that letter is x. This is why a nominative in -x is a reliable sign of a base in -c- or -g-.

iūdic + s = iūdex; rēg + s = x; duc + s = dux.

VSelf-check

Six out of six before you start the exercises.

Question 1

Why does the nominative rēx look nothing like its own genitive rēgis?

Right. That is Rule 7. Nothing is dropped: rēg + s merge into the single letter x, exactly as iūdic + s gives iūdex and duc + s gives dux. The -g is not replaced — it is still there, inside the x.

Not quite — the x is doing the work of two letters at once. Ask yourself which two.

Question 2

What is the base of virtūs, virtūtis?

Right. Rule 4: drop -is from the genitive singular virtūtis and virtūt- is what remains. Never take the base from the nominative — virtūs would have misled you into virtūs- or virtū-, and neither will decline.

Not quite — the nominative is the one form you must not use here. Go to the genitive and remove its ending.

Question 3

Mīles stands for an earlier mīlets. Which rule accounts for the missing letter?

Right. Rule 6 — the -t of mīlit- falls away before the nominative -s, and the same happens in lapis (for lapids) and virtūs (for virtūts). Option c is a real rule and also applies to mīles, but it explains the vowel e, not the vanished t.

Not quite — two things changed between mīlit- and mīles. The question asks only about the letter that disappeared.

Question 4

Most two-syllable nouns show i in the base but e in the nominative. Which of these is the exception named in the lesson?

Right. Rule 5: prīnceps (base prīncip-) and iūdex (base iūdic-) both swap their base i for e in the nominative, but lapis keeps the i of lapid- straight through.

Not quite — write each nominative beside its base and look only at the vowel. Two of them change it; one does not.

Question 5

In a consonant stem, how does the stem relate to the base?

Right. Rule 2. That is precisely what makes it a consonant stem: no vowel is appended, so the stem ends in the base's own final consonant — rēg-, virtūt-, lapid-. Adding -i- (option a) would make it an i-stem, and adding -ā- (option b) is the first declension.

Not quite — the declension is named after the letter its stems end in. If a vowel were added, what letter would the stem end in?

Question 6

Which is the genitive plural of eques, equitis?

Right. Base equit- plus the genitive plural termination -um gives equitum, "of the horsemen." Equitōrum borrows the second declension's -ōrum, which this declension never uses; and equitium is the i-stem shape — that extra i is exactly what a consonant stem does not have.

Not quite — find -um in the terminations column of the table above, and add it straight onto the base.

Answered correctly: 0 / 6