Noun Endings (1st-3rd Declension)

Table of contents

1. Noun Endings
   1. 1st Declension
   2. 2nd Declension
      1. 2nd Declension Masculine/Feminine
      2. 2nd Declension Neuter
   3. 3rd Declension
      1. 3rd Declension Masculine/Feminine
      2. 3rd Declension Neuter

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Noun Endings

While the gender of nouns cannot be changed, the case and number of nouns does change to reflect a noun’s different functions within a sentence (case) and how many there are of the noun (number). These different case-number combinations are indicated by the use of certain endings that get applied to a noun’s stem. As discussed in the nouns overview, the specific ending used to reflect a certain case-number combination depends on the noun’s declension. As a reminder, we determine a noun’s declension based on the ending of its second principal part in its dictionary entry:

(We’ll learn about the 4th and 5th declension in a later lesson.)

The second principal part also gives us that noun’s stem – we take off that ending (-ae, -ī, or -is), and we use what is left of the noun to attach appropriate endings for the noun’s case and number.

The endings that can be applied to reflect different cases and numbers in nouns are as follows. We’ll discuss the specific uses of each case in the next units; for now, this is simply about rote morphology and learning how each of the case-number combinations can appear in the 1st through 3rd declensions.

These endings must be memorized. Having them in your head rather than needing to look them up every time you need to check the case and number of a noun will save you a lot of time and stress in the long run.

1st Declension

All nouns in the first declension will use the following endings:

Note the macron (long mark) over the -ā in the ablative singular: this is an important long mark that will be the only way to differentiate the ablative singular from the nominative singular. Note also the endings that can be used in multiple instances: -ae for genitive singular, dative singular, and nominative plural; and -īs for dative plural and ablative plural. We’ll learn much more about how to use context to tell these apart later.

Here is an example of a full declension chart of a first declension noun: puella, puellae, f. - girl. We first need to determine the noun’s stem by removing the ending from the 2nd principal part, leaving us with the stem puell-. Then, we can add the appropriate endings.

2nd Declension

There are two sets of endings for second declension nouns depending on the noun’s gender, whether it’s masculine/feminine or neuter. Thus, once you’ve determined that a noun is 2nd declension because of the -ī in its genitive singular form, you then have to determine the noun’s gender to apply the correct ending chart.

2nd Declension Masculine/Feminine

As in the 1st declension, note the endings that are used in multiple places: -ī for genitive singular and nominative plural, -ō for dative and ablative singular, and -īs for dative plural and ablative plural.

Here is an example of a full declension chart of a 2nd declension masculine noun: puer, puerī, m. - boy, with the stem puer-:

2nd Declension Neuter

The endings for 2nd declension neuter are mostly similar to those of 2nd declension masculine/feminine except for the nominative singular (-um) and the nominative and accusative plural (-a). This is our first example of an important rule: in a neuter noun, adjective, or pronoun, the nominative singular and accusative singular will be exactly identical, as will the nominative plural and accusative plural.

Here is an example of a full declension chart of a 2nd declension neuter noun: oppidum, oppidī, n. - town, with the stem oppid-:

3rd Declension

The 3rd declension, like the 2nd declension, has two sets of endings depending on the noun’s gender, masculine/feminine or neuter.

3rd Declension Masculine/Feminine

The – in the nominative singular means that there is a lot of variety in nominative singular forms of 3rd declension nouns; there is no one set ending. As usual, note the duplications: -ēs in the nominative and accusative plural and -ibus in the dative and ablative plural.

Here is an example of a full declension chart of a 3rd declension masculine noun: dux, ducis, m. - leader, with the stem duc-:

3rd Declension Neuter

The accusative singular of a 3rd declension neuter noun will look exactly like the nominative singular form, however it’s spelled, due to the rule mentioned above. Other forms that differ from 3rd declension masculine/feminine include the nominative and accusative plural (-a).

Here is an example of a full declension chart of a 3rd declension neuter noun: nōmen, nōminis, n. - name, with the stem nōmin-:

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