Lesson 09. Of Nouns: Second Declension

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We now move forward to the study of the Second Declension of nouns. In our earlier work we learned how First Declension nouns are declined, using examples such as haec Musa, hic Aeneas, hic Anchises, and haec Penelope. We also learned the essential principle that a noun’s declension is known not by the ending of its Nominative case, but by the ending of its Genitive singular. For First Declension nouns, the Genitive singular ends in -ae, or in -es when the Nominative ends in -e.

With that principle firmly in mind, we are prepared to study the Second Declension. Just as there were several possible Nominative endings in the First Declension, there are also several possible Nominative endings in the Second Declension. These endings include -er, -ir, -us, and -um. The example nouns that will guide us are hic Liber meaning “a book,” hic Vir meaning “a man,” hic Dominus meaning “a lord,” and hoc Templum meaning “a temple.”

However, we must be careful not to make the mistake of identifying a noun’s declension by its Nominative ending alone. A noun does not belong to the Second Declension simply because it ends in -er, -ir, -us, or -um in the Nominative. The only reliable way to determine a noun’s declension is by examining the ending of its Genitive singular. All Second Declension nouns have a Genitive singular ending in -i. This Genitive ending, and not the Nominative form, is what makes a noun a Second Declension noun.

Second Declension nouns are extremely common, and we have already encountered many of them in our reading of the Gospel of John. Words such as dominus, Deus, principium, Verbum, testimonium, mundus, filius, vir, unigenitus, Christus, responsum, and desertus all belong to the Second Declension. As we continue our reading, we will see these forms repeatedly, which makes careful study at this stage especially important.

We begin with Second Declension nouns whose Nominative singular ends in -er or -ir, such as hic Liber and hic Vir. In these nouns, the Genitive singular ends in -i, the Dative singular ends in -o, the Accusative singular ends in -um, the Vocative singular is the same as the Nominative, and the Ablative singular ends in -o. In the plural number, the Nominative ends in -i, the Genitive in -orum, the Dative in -is, the Accusative in -os, the Vocative is the same as the Nominative, and the Ablative ends in -is.

When we decline hic Liber, we say Liber in the Nominative singular meaning “a book,” Libri in the Genitive singular meaning “of a book,” Libro in the Dative singular meaning “to a book,” Librum in the Accusative singular meaning “a book,” O Liber in the Vocative, and a Libro in the Ablative meaning “from a book.” In the plural we say Libri, Librorum, Libris, Libros, O Libri, and a Libris. It is important to notice that the stem of this noun is Libr-, not Liber-, and that the endings are added to this stem.

Next we study Second Declension nouns whose Nominative singular ends in -us, such as hic Dominus. These nouns follow the same pattern as Liber in most cases, but they differ in the Vocative singular. Instead of remaining the same as the Nominative, the Vocative singular changes from -us to -e. Thus we say Dominus in the Nominative singular, Domini in the Genitive, Domino in the Dative, Dominum in the Accusative, O Domine in the Vocative, and a Domino in the Ablative. In the plural, these nouns follow the same forms as Liber: Domini, Dominorum, Dominis, Dominos, O Domini, and a Dominis. One exception must be remembered: the noun Deus does not change to Dee in the Vocative, but remains O Deus.

We also encounter proper nouns ending in -ius, such as Antonius. These nouns follow the same general pattern as nouns ending in -us, but their Vocative singular ends in -i rather than -e. Thus we say O Antoni and similarly O fili from filius.

Another group of Second Declension nouns ends in -eus, such as Orpheus. These nouns form the Vocative singular in -eu, so we say O Orpheu, while all other cases follow the regular Second Declension pattern.

We then come to Second Declension nouns whose Nominative singular ends in -um, such as hoc Templum. These nouns are Neuter, and this fact has important consequences for their declension. In the singular number, Templum appears as Templum in the Nominative, Templi in the Genitive, Templo in the Dative, Templum again in the Accusative, O Templum in the Vocative, and a Templo in the Ablative. In the plural number, Neuter nouns follow a special rule: the Nominative, Accusative, and Vocative are all the same. Thus we say Templa in the Nominative plural, Templorum in the Genitive, Templis in the Dative, Templa in the Accusative, O Templa in the Vocative, and a Templis in the Ablative.

All Second Declension nouns ending in -um are Neuter, and this leads us to a general rule that applies to Neuter nouns in every declension. In both the singular and the plural, Neuter nouns have the Nominative, Accusative, and Vocative cases alike. In the plural, these cases end in -a, with the exception of the words ambo and duo, which end in -o.

As we study these forms, we must remember that learning declensions requires work in two directions. When reading Latin, we must be able to look at a form and know all of the possible meanings it may have. When writing Latin, we must be able to start with an English phrase, such as “of a book” or “to a temple,” and know exactly which Latin form to use. For example, the word libri may mean “of a book” as a Genitive singular, or “books” as a Nominative plural. The correct translation can only be determined by context.

The same principle applies to adjectives. When an adjective is used with a substantive, it must agree with that noun in gender, number, and case. Thus we say vir magnus meaning “a great man,” viro magno meaning “to a great man,” O vir magne meaning “O great man,” and virorum magnorum meaning “of great men.” With Neuter nouns we say templum sanctum meaning “a holy temple,” O templum sanctum, a templo sancto, and in the plural templa sancta. When the substantive and adjective belong to different declensions, their forms may look different even though they agree in case, number, and gender, as in vir sapiens, viri sapientis, O vir sapiens, and viris sapientibus. This may seem difficult now, but it will become clear once all declensions are learned.

For now, our task is not to resolve every difficulty, but to learn the forms accurately and completely. We memorize, we write, and we practice until the Second Declension is as familiar as the First. Once the forms are secure, reading and writing Latin will become steadily easier.

Memory Work

With this lesson, we review the rules of the first declension of Latin nouns.

1. How many different terminations are found in the Nominative case of the Second Declension?
Four: -er, as hic Liber (a book); -ir, as hic Vir (a man); -us, as hic Dominus (a Lord); -um, as hoc Templum (a Temple).

2. How are Second Declension nouns with Nominative in -er and -ir declined?
As hic Liber and hic Vir: with Genitive in -i; Dative in -o; Accusative in -um; Vocative like the Nominative; Ablative in -o. In the plural, Nominative in -i; Genitive in -orum; Dative in -is; Accusative in -os; Vocative like the Nominative; Ablative in -is.

In short: -er/-ir, -i, -o | -um, -er/-ir, -o | -i, -orum, -is | -os, -i, -is.

3. Decline the Second Declension noun hic Liber. (State the case name, the Latin form and the English.)
Singulariter: Nominativo, hic Liber, a Book; Genitivo, Libri, of a Book; Dativo, Libro, to a Book; Accusativo, Librum, a Book; Vocativo, O Liber, O Book; Ablativo, a Libro, from a Book. Pluraliter: Nominativo, Libri, Books; Genitivo, Librorum, of Books; Dativo, Libris, to Books; Accusativo, Libros, Books; Vocativo, O Libri, O Books; Ablativo, a Libris, from Books.

In short: Liber, Libri, Libro | Librum, O Liber, a Libro | Libri, Librorum, Libris | Libros, O Libri, a Libris.

Note: The stem of the noun Liber is Libr-, so endings are not added to liber but libr-.

4. How are Second Declension nouns with Nominative in -us declined?
Nouns that end in -us have the Nominative in -us, as Dominus, a Lord; Vocative, O Domine, O Lord, except Deus, O Deus, O God.

In short: -us, -i, -o | -um, -e, -o | -i, -orum, -is | -os, -i, -is.

5. Decline the Second Declension noun hic Dominus. (State the case name, the Latin form and the English.)
Singulariter: Nominativo, hic Dominus, a Lord; Genitivo, Domini, of a Lord; Dativo, Domino, to a Lord; Accusativo, Dominum, a Lord; Vocativo, O Domine, O Lord; Ablativo, a Domino, from a Lord. Pluraliter: as Liber.

In short: Dominus, Domini, Domino | Dominum, O Domine, a Domino | Domini, Dominorum, Dominis | Dominos, O Domini, a Dominis.

6. How are Second Declension Proper nouns with Nominative in -ius declined?
Proper Nouns that end in -ius, have the Vocative in -i, as Antonius, O Antoni. To this we may add filius (a son), O fili.

In short: -ius, -i, -o | -um, -i, -o | -i, -orum, -is | -os, -i, -is.

7. How are Second Declension nouns with Nominative in -eus declined?
Nouns that end in -eus, have the Vocative in -eu, as Orpheus, O Orpheu.

In short: -eus, -i, -o | -um, -eu, -o | -i, -orum, -is | -os, -i, -is.

8. How are Second Declension nouns with Nominative in -um declined?
As hoc Templum: with Genitive in -i; Dative in -o; Accusative and Vocative like the Nominative; Ablative in -o. In the plural, Nominative in -a; Genitive in -orum; Dative in -is; Accusative and Vocative like the Nominative; Ablative in -is.

In short: -um, -i, -o | -um, -um, -o | -a, -orum, -is | -a, -a, -is.

9. Decline the Second Declension noun hoc Templum. (State the case name, the Latin form and the English.)
Singulariter: Nominativo, hoc Templum, a Temple; Genitivo, Templi, of a Temple; Dativo, Templo, to a Temple; Accusativo, Templum, a Temple; Vocativo, O Templum, O Temple; Ablativo, a Templo, from a Temple. Pluraliter: Nominativo, Templa, Temples; Genitivo, Templorum, of Temples; Dativo, Templis, to Temples; Accusativo, Templa, Temples; Vocativo, O Templa, O Temples; Ablativo, a Templis, from Temples.

In short: Templum, Templi, Templo | Templum, O Templum, a Templo | Templa, Templorum, Templis | Templa, O Templa, a Templis.

10. What is special about Second Declension nouns ending in -um?
All Second Declension nouns ending in -um are of the Neuter gender.

11. What special rules apply to the declension of Neuter Nouns?
Neuter Nouns, in any declension, have three cases alike in both numbers: the Nominative, the Accusative and the Vocative, which always end in -a in the Plural, except for the words ambo and duo, which end in -o.

12. Summary of the Second Declension:

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