Third Declension
Magister Riggs
Third Declension Latin Nouns
•
Third Declension
written by: John Garger • edited by: Tricia Goss • updated: 12/7/2011
•
The third declension of Latin follows the same rules as the previous two.
However, third declension nouns have irregular nominative singular forms.
Learn how to form Latin nouns of the third declension.
1
Latin is an inflected language, meaning the endings of Latin words change to
indicate their function in a sentence (e.g. subject, direct object, indirect
object). Latin nouns are declined in one of five declensions, the third of which
is the most widely used in the language. Luckily, by the time beginning
students encounter the third declension, they have experience with the quirks
and irregularities of the first two.
Unlike the previous two declensions, third declension nouns may be any of
the three genders, masculine, feminine or neuter. Every third declension noun
is characterized by the genitive ending –is as in regis (masculine), virtutis
(feminine), and corporis (neuter). However, unlike. the characteristic
nominative singular ending of the first (–a) and second (–us, –um)
declensions, the third declension has no characteristic word ending. Thus, it
is vital to memorize the gender of all nouns as well as the genitive form of the
word so it is obvious to which declension it belongs and how it is properly
declined
1Third Declension Forms for Masculine and Feminine Nouns
Third declension nouns are formed just as in the previous two declensions; the
endings are added to the base of the word. However, one complexity of third
declension nouns is that the base sometimes changes from the nominative to the
other cases. This is why learning the nominative form of a noun is not enough.
Always memorize the genitive of every noun so their forms are immediately
familiar when encountered in text. Luckily, masculine and feminine nouns are
declined exactly the same so no new forms must be memorized. Unfortunately,
similar forms mean no clue is given as to a noun’s gender. Again, memorization is
the key. A masculine noun is declined as follows:
3rd declension masc. and fem. Sing.
Singular
•
•
•
•
•
nom. rex
gen. regis
dat. regi
acc. regem
abl. rege
3rd declension Masc. and Fem.
Plural
•
•
•
•
•
nom. reges
gen. regum
dat. reginbus
acc. reges
abl. regibus
Plural
3rd declension Masc. and Fem.
Notice that the base for all cases is different from the nominative singular. It
may help to know that rex was originally regs in earlier Latin. However, the –
gs sound is so similar to –x that it changed by the time Classical Latin was
spoken. Remember that a language is spoken first and written later. This is
especially true of ancient languages at a time when the majority of the
population was illiterate.
•
The singular forms of third declension masculine and feminine nouns all have
different endings, so there is no confusion for beginning students other than
memorizing the new endings. Notice that in the genitive plural, the familiar –
um is present, similar to the –orum of second declension nouns and –arum or
the first declension. The nominative and accusative plural has the same form,
like second declension neuter nouns. The plural dative and ablative forms are
similar, as they are in the previous two declensions, although the endings are
different here in the third declension.
3rd declension-neuter nouns
Third Declension Forms for Neuter Nouns
•
Third declension neuter nouns prove a bit more difficult for beginning
students because although they often change form from the nominative to the
genitive, they also have the same form for nominative and accusative in the
singular. Pay close attention to the gender of a third declension noun to avoid
common mistakes. For example
•
Singular
•
nom. corpus
•
gen. corporis
•
dat. corpori
•
acc. corpus
•
abl. corpore
•
Plural
•
nom. corpora
•
gen. corporum
•
dat. corporibus
•
acc. corpora
•
abl. corporibus
3rd declension-neuter nouns
Notice that the forms are similar to the masculine and feminine forms with two
exceptions. The nominative and accusative singular have the same form. The
accusative form reverts back to the nominative form. This often gives
students trouble because they become used to the shift in spelling for the
other cases and forget that the accusative must look exactly like the
nominative. Also, notice the characteristic –a ending for the nominative and
accusative plural, a form familiar from neuter nouns of the second declension.
The word corpus often gives students trouble in the genitive singular because
the –orum looks like the ending for a second declension noun. The stem of
the word is corpor– and the ending is –um. It is only coincidental that the form
looks like the –orum ending from the second declension.