1. Noun Review: Third Declension Neuter Nouns
Magister Henderson
Latin II

2. Third Declension Neuter Noun
In addition to the masculine and feminine nouns, there are also neuter nouns in the third declension.
Though the masculine feminine and neuter nouns share the same ending, neuter nouns have their own slightly different endings.
As in the second declension, neuter nouns will always match in the nominative and accusative cases.

3. Third Declension Neuter Endings
Singular
Plural
Nominative
n/a -a
Genitive
-is
-um
Dative -ī
-ibus
Accusative
Ablative -e
As with other third declension nouns, there is no standard nominative singular ending for neuter third declension nouns.
The accusative, which by rule must match the nominative, will also have no standard ending.

4. tempus, temporis n. = “time”
Singular
Plural
Nominative
tempus
tempora
Genitive
temporis
temporum
Dative
temporī
temporibus
Accusative
Ablative
tempore
The noun tempus, temporis is a typical third declension neuter noun.
Notice how the genitive singular base tempor- (rather than the nominative singular tempus) is used to form the remaining forms.

5. Third Declension i-stem Nouns
The i-stem nouns are a subgroup of the third declension.
For neuter i-stems, the genitive plural changes to –ium and the nominative and accusative plurals changes to -ia.
The ablative singular of neuter i-stems will always change to –ī, matching the dativie singular form..

6. mare, maris, marium n. = “sea”
Singular
Plural
Nominative
mare
maria
Genitive
maris
marium
Dative
marī
maribus
Accusative
Ablative
The noun mare, maris is a third declension i-stem noun that may be either masculine or feminine.
Notice how the genitive singular base mar- is identical to the nominative singular base. Also notice plurals in –ia and –ium rather than –a and –um.

7. Third Declension Neuter Nouns
animal, animalis, animalium = animal
caput, capitis = head
corpus, orporis = body
flūmen, flūminis = river
iūs, iūris = right, law
iter, itineris = journey
onus, oneris = burden
opus, operis = work