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Latin Grammar I, Lesson 11. The First Declension of Nouns

To complete this lesson, complete the following tasks:

  1.  Study the Lesson for mastery.
  2. Complete all assignment Memory Work.
  3. Complete all lesson Assessments.


1. In lesson 03, we were introduced to the “accidents” of the parts of speech.  In that lesson, I said:  “In this lesson, we will learn a little about each of these accidents, and then we will study them in detail throughout the rest of the course.”  In this lesson, we begin our detailed study of the declensions of Latin nouns.

In lesson 03, we learned that he Declensions of nouns are five.

The First declension, whose genitive singular is ended with the diphthong -AE, as musamusae.
The Second declension, whose genitive singular is ended with the letter -I , as dominusdomini.
The Third declension, whose genitive singular is ended with (the) syllable -IS , as sermosermonis.
The Fourth declension, whose genitive singular is ended with the syllable -US , as sensussensus.
The Fifth declension, whose genitive singular is ended with the letters E and I, as diesdiei.

In this lesson, we will study the forms of the First Declension nouns.

Example Noun of the First Declension

2.  The example noun for the First Declension is haec musa, which means “a muse”.  In classical mythology, a muse was a spirit who was believed to inspire artists.  For example, when Homer begin his poem, the Odyssey, he begins by praying. “Tell me, O Muse, of that ingenious hero who travelled far and wide after he had sacked the famous town of Troy.”  Almost all first declension nouns in Latin are declined like haec musa.

Nomimativehaecmus-a(the) musemus-ae(the) muses
Genitivemus-aeof (the) musemus-arumof (the) muses
Dativemus-aeto (the) musemus-isto (the) muses
Accusativemus-am(the) musemus-as(the) muses
VocativeOmus-aO museOmus-aeO muses
Ablativeamus-afrom (the) museamus-isfrom (the) muses

Understanding the Declension Chart

The declension chart above contains all of the information you need to know about nouns of the first declension.  We should take some time to learn about this chart, since you’ll be studying it in many of your future lessons.

Nouns are one of the four parts of speech that are declined, and that nouns possess a number of “accidents” or characteristics.

The first of these is number.  At the top of the chart, you can see the two numbers labeled:  Singular and Plural.  The noun forms on the left are singular in number; the noun forms on the right are plural in number.

The second of the accidents of nouns is case.   On the left side of the chart, you can see the six cases of nouns listed:  Nominative, Genitive, Dative, Accusative, Vocative and Ablative.  If you look across each row, you will see the singular and plural form of the noun for each case.

The third of the accidents of nouns is gender.  If you find the Nominative case row, and look to the second column, you will see the pronoun haec.  This is the femine form of the pronoun hichaechoc, and it tells us that the gender of the noun musa is feminine.  If the noun is mascculine, the pronoun will be hic. If it is neuter, the pronoun will be hoc.  We refer to this noun as haec musa, which tells us the noun is feminine.

The cases signify the relationship between the noun and other words in the sentence.  The Nominative case normaly signifies that the noun is the subject of the sentence. The Genitive case signifies that the noun is the possessor or source of something.  The Dative case signifies that the noun is the indirect object the verb, “to” or “for” whom the action of the verb is done.  The Accusative case signifies the direct object of the verb, onto which the action of the verb passes.  The Vocative case signifies that the noun names a person being spoken to directly.  Lastly, the Ablative case normally signifies that the noun names a thing in which, from which, by which, with which, etc., some other part of the sentence relates.  The exact meaning of the Accusative and Ablative cases are normally determined by the meaning of prepositions that go before them, as we’ll see.  We use the cases to direct us in constructing and interpreting Latin sentences.

In the second and sixth columns, we see signs of the Vocative and Ablative cases.  To help with our studies, since some forms are the same, we use these signs to mark the different cases. Since we use the interjection O when we call somone, as “O Lord!”, it is used as a sign of the Vocative case.  Since the preposition ab or a expresses the common idea of the Ablative case (“from”), we use it for the sign of that case.  Again, the uses of these signs is simply for the study of the Latin noun declensions.

In the third and seventh columns, we see the Latin forms for each case in the singular and plural number.  So, the Genitive, Singular form for the noun haec musa is musae, and the Genitive plural form is musarum.  The first part of the word, which contains the meaning of the noun is called the “stem”.  The second part of the word, which comes after the hyphen, markes the case and number, and is called the “termination” or “ending”.  We also use the Genitive Singular form to find the stem of any noun.  You’ll see why when we study the hird declension of nouns.

Lastly, in the fourth and eighth columns, we see the English meaning for each of the forms of the noun.  There are no articles (a, an, the) in Latin, so we add them in the English just to make the language clear.  Thus, the Genitive Singular form musae can mean:  “of muse”, “of (a) muse” or “of (the) muse”.  The Dative Plural form musis can mean “to muses”, “for muses”, “to (the) muses” or “for (the) muses”.  On your online exams, any of these correct forms should be marked correct, so you don’t need to worry about that.

Learning for Translation and Composition

When studying noun forms, we must learn them in two directions. In order to read Latin, we must learn to translate the forms from Latin into English. So when you see a Latin noun, you should know exactly how it should be translated or “turned” into English.  In order to write or speak in Latin, we must learn to translate the forms from English into Latin. So when we see an English word or phrase, like “of (the) muse”, we must know which form to use to turn it into Latin.  We will practice studying nouns in both directions.  Our practice with these forms will come (a) through memorizing the rules carefully, (b) writing out the declensions daily and (c) completing the online quizzes.  Be sure you complete all assigned lesson exercises every day and rely on memorization at this time to help you.

Substantives and Adjectives

4. We have learned about two classes of Nouns: Substantives and Adjectives.  We learned that an adjective noun may be used with a substantive that is expressed or understood. For example, we say lux vera (a true light).  Lux is an expressed substantive, vera is an adjective noun. Adjective nouns have cases just like substantives, so when they are used together, they must always be written with the same gender, number and case. This can be pretty easy when we use adjectives of the first declension:

musa jucunda            a pleasant Muse
musae jucundae        of a pleasant Muse
O musa jucunda        O pleasant Muse

pulchra Penelope       fair Penelope
O pulchra Penelopa   O fair Penelope
a pulchra Penelopa    from fair Penelope

This can be difficult, however, when the Substantive noun is from the First Declension, and the Adjective is from another declension. Then, the cases will not look the same. For example, the substantive noun musa is from the First Declension, but the adjective dulcis is from the third declension. When used together, they will look like this:

musa dulcis               a sweet Muse
musae dulcis             of a sweet Muse
O musa dulcis           O sweet Muse

We saw this in our reading with the phrase lux vera.  Lux is a third declension substantive and vera is a First Declension adjective. This makes writing substantives and adjectives difficult, but you do not need to understand this now.  It will be much clearer after you have learned all of the declensions.  Pay attention to adjectives and substantives in your Latin Reading translations.  (You are studying your Latin Reading lessons, right?)

Memory Work

To learn the declensions, you must relay on memorization.  Recite the questions and answers below until they are thoroughly memorized.  Rely on the lesson assessments to test your progress.

1. What is the example noun of the First Declension?
The example noun of the first declension is haec musa, (the) muse.

2.  How are nouns of the First Declension identified?
Nouns of the First Declension are identified by the Genitive Singular ending in the diphthong -AE.

3. How are nouns of the first declension declined?
Nouns of the first declension are declined as haec musa;  in the Singular with Nominative in -a; Genitive and Dative in -ae; Accusative in -am; Vocative in -a; Ablative in -a. In the plural, Nominative in -ae; Genitive in -arum; Dative in -is; Accusative in -as; Vocative like the Nominative; Ablative in -is.   In short: -a, -ae, -ae, -am, -a, -a; -ae, -arum, -is, -as, -ae, -is.

4. Decline the First Declension noun haec Musa. (State the case name, the Latin form and the English.)
In the Singular number: Nominative, haec Musa, a Muse; Genitive, Musae, of a Muse; Dative, Musae, to a Muse; Accusative, Musam, a Muse; Vocative, O Musa, O Muse; Ablative, a Musa, from a Muse.  In the Plural number: Nominative, Musae, Muses; Genitive, Musarum, of Muses; Dative, Musis, to Muses; Accusative, Musas, Muses; Vocative, O Musae, O Muses; Ablative, a Musis, from Muses.  In short, in the Singular:  MusaMusaeMusaeMusamO Musaa Musa; Plural: MusaeMusarumMusisMusasO Musaea Musis.

5. What is meant by the words “of”, “to”, “O” and “from” used when declining?
These words “of”, “to”, “O” and “from” are signs of the Cases with which they are joined, and are put to all Nouns. “Of” signifies the Genitive case. “To” signifies the Dative case. “O” signifies the Vocative case. “From” signifies the Ablative case. The Nominative and Accusative cases are not known by signs, but by their position in a sentence.

6. Are there places where these rules do not apply?
Yes. In some words, such as dea (goddess)filia (daughter)ambae (both) and duae (two), the Dative and Ablative cases end in -abus, rather than -isThis is to distinguish them from their masculine forms like deus and filius.

7. Summary of the First Declension:

Nomimativehaecmus-a(the) musemus-ae(the) muses
Genitivemus-aeof (the) musemus-arumof (the) muses
Dativemus-aeto (the) musemus-isto (the) muses
Accusativemus-am(the) musemus-as(the) muses
VocativeOmus-aO museOmus-aeO muses
Ablativeamus-afrom (the) museamus-isfrom (the) muses


Latin Grammar I, Lesson 11 Exam