1. Noun Review: Third Declension Masculine and Feminine Nouns
Magister Henderson
Latin II

2. About the Third Declension
The third declension is the largest of Latin’s five noun declensions.
It contains a mix of masculine, feminine, and neuter nouns.
There is a subgroup of third declension nouns, called i-stems that add an “i” before the genitive plural ending.
The nominative singular ending varies word to word in the third declension.

3. Third Declension Noun Endings
Singular
Plural
Nominative
n/a
-ēs
Genitive
-is
-um
Dative -ī
-ibus
Accusative
-em
Ablative -e
There is no standard nominative singular ending. The stem of the noun is derived from the genitive singular form.
Third declension masculine and feminine nouns have identical endings.

4. pater, patris m. = “father”
Singular
Plural
Nominative
pater
patrēs
Genitive
patris
patrum
Dative
patrī
patribus
Accusative
patrem
Ablative
patre
The noun pater, patris is a typical third declension masculine noun.
Notice how the genitive singular base patr- (rather than the nominative singular pater) is used to form the remaining forms.

5. vox, vocis f. = “voice”
Singular
Plural
Nominative
vox
vocēs
Genitive
vocis
vocum
Dative
vocī
vocibus
Accusative
vocem
Ablative
voce
The noun vox, vocis a typical third declension feminine noun.
Notice how the genitive singular base voc- (rather than the nominative singular vox) is used to form the remaining forms.

6. Third Declension i-stem Nouns
The i-stem nouns are a subgroup of the third declension.
For masculine and feminine i-stems, the only difference from regular third declension nouns will be the the genitive plural ending in –ium.
To distinguish i-stem nouns they will be listed in three principal parts, with the third form being the genitive plural.

7. civis, civis, civium m./f. = “citizen”
Singular
Plural
Nominative
civis
civēs
Genitive
civium
Dative
civī
civibus
Accusative
civem
Ablative
cive
The noun vox, vocis is a third declension i-stem noun that may be either masculine or feminine.
Notice how the genitive singular base civ- is identical to the nominative singular base. Also notice the genitive plural in –ium rather than –um.

8. Third Declension Masculine Nouns
adulescēns, adulenscentis = young man
clamor, clamoris = shout
dens, dentis, dentium = tooth
fragor, fragoris = crash
frater, fratris = brother
hostis, hostis, hostium = enemy
milēs, militis = soldier
princeps, principis = emperor

9. Third Declension Feminine Nouns
arbor, arboris = tree
ars, artis, artium = skill, art
finis, finis, finium = end
mater, mātris = mother
mulier, mulieris= woman
pars, partis, partium = part
soror, sororis= sister
urbs, urbis, urbium = city