How To Find the Stem of Any Latin Noun (Easily!)
You need to know the stem of a Latin noun in order to be able to decline it. In this post, learn how to find the stem of any Latin noun!
First of all, let’s review what a stem is. The stem is the part of the noun that the case endings are added to. It is the basic form of the word that appears in all case forms except the nominative singular of third declension nouns and a few second declension nouns (and the accusative singular, for third declension neuter nouns).
The stem is also what allows you to identify the word and establish its meaning. So being able to determine the stem of a noun is crucial.
(Some people call this the base instead of the stem. But don’t worry – the process of finding the stem/base is the same, no matter what you call it.)
Let’s get started!
How to find the stem of a Latin noun
Fortunately, finding the stem of a Latin noun is quite simple. You simply look at the genitive singular and remove the case ending. Whatever you have left is the stem.
Here are the genitive singular endings for the different declensions:
FIRST: -ae
SECOND: -ī
THIRD: -is
FOURTH: -ūs
FIFTH: -eī / ēī
When you see the genitive singular of a noun, simply remove the ending and you will have the stem. (You also use the genitive singular to determine the declension of a Latin noun.)
Now let’s look at an example noun. The dictionary form of the noun is the nominative singular followed by the genitive singular. So you want to look at the second word to determine the stem.
mater, matris
What is the stem of mater, matris?
Well, mater, matris is third declension. So we take the -is off of the genitive singular.
matris – is = matr–
This means that our stem is matr-!
Okay, time to practice. What is the stem of each of the following nouns?
- mōns, montis
- exercitus, exercitūs
- verbum, verbī
- iter, itineris
- sella, sellae
- rēs, reī
- mūrus, mūrī
- agricola, agricolae
- montis – is = mont-
- exercitūs – ūs = exercit-
- verbī – ī = verb-
- itineris – is = itiner-
- sellae – ae = sell-
- reī – eī = r-
- mūrī – ī = mūr-
- agricolae – ae = agricol-
Still with me? Let’s address a few potential issues.
Why can’t we find the stem of a Latin noun from the nominative?
You may have noticed that, in most of the words above, the stem was also present in the nominative singular. So, you ask, why can’t we just take the ending off the nominative? Why do we need to look at the genitive singular?
Well, you can simply take the ending off of the nominative – for all declensions EXCEPT third declension (and a few –er nouns in second declension).
If we look back at #1 and #4 in Exercise 1, we notice something. The stem of mōns is mont– and the stem of iter is itiner-. The stem is NOT present in the nominative. So we really do need to know the genitive in order to find the stems of third declension nouns.
Because we already need to memorize the genitive anyway to determine the declension of a noun, it makes sense to simply remove the genitive ending to find the stem because this ALWAYS works. No exceptions.
TIP: Be extra careful with third declension nouns. Their stems can be weird and unpredictable.
What if the dictionary doesn’t give the full genitive singular?
Most beginning Latin textbooks and resources will give you the full nominative and genitive singular for each noun. But since first, second, fourth, and fifth declension stems are very regular, often dictionaries use shorthand.
FIRST DECLENSION: sella, sellae becomes sella, ae. When this happens, to get the stem you can remove the nominative singular ending -a.
SECOND DECLENSION: mūrus, mūrī becomes mūrus, ī; so so remove the -us.
FOURTH DECLENSION: exercitus, exercitūs becomes exercitus, ūs; so remove the -us.
FIFTH DECLENSION: rēs, reī becomes rēs, eī; so remove the -ēs.
But for third declension, dictionaries will include the full genitive singular.
More Practice With 3rd Declension Nouns
Since 3rd declension stems can be so weird, let’s do another quick exercise. Find the stems of the following four nouns.
- nox, noctis
- flūmen, flūminis
- iuventūs, iuventūtis
- missiō, missiōnis
- noctis – is = noct-
- flūminis – is = flūmin–
- iuventūtis – is = iuventūt–
- missiōnis – is = missiōn–
Okay, how are you feeling? We just have one more topic to address, and then you will know how to find the stem of any Latin noun.
How to Find the Stem of a Plural-Only Noun
Some Latin nouns (called pluralia tantum or plural-only) have no singular forms. In other words, they only exist in the plural. In consequence, you cannot remove the genitive singular ending to find the stem. Instead, you have to remove the genitive plural ending.
Or, if the dictionary form is abbreviated (as it typically will be for plural-only nouns), you must remove the nominative plural ending.
Here are the nominative and genitive plural endings of the five declensions.
FIRST: -ae, ārum
SECOND: -ī, ōrum (masculine); a, ōrum (neuter)
THIRD: -ēs, um/ium (masculine/feminine); a/ia, um/ium (neuter)
FOURTH: -ūs, uum (masculine); ua, uum (neuter)
FIFTH: -ēs, ērum
Practice identifying the stems of the following plural-only Latin nouns.
- moenia, ium
- Quinquātrūs, uum
- angustiae, ārum
- arma, ōrum
- moenia – ia = moen-
- Quinquātrūs – ūs = Quinquātr–
- angustiae – ae = angusti–
- arma – a = arm–
And there you have it. Now you know how to find the stem of any Latin noun. I hope that you have found my explanations and exercises helpful. And good luck on your Latin journey!
Make sure you follow my new @latinwithlivia account on Instagram. I will be sharing lots of Latin study tips and trivia, as well as fun facts about ancient Rome. Don’t miss out!
Oh, and are you wondering what the genitive case even does? I know we have talked about it a lot in this post! If you’re curious, you can read all about the genitive case here.
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Is Needham — as in Needham, MA — a declinable noun of the third declension? Or is it indeclinable — like Capharnaum and Ierusalem? Thank you!
Hi Dan, great question! Modern city names like this are tricky. Since there doesn’t seem to be an established Latin name for Needham, you have two options.
1. Treat Needham like an indeclinable noun (as you suggested).
2. Latinize the name. Latin Wikipedia calls Birmingham “Birminghamia”, Nottingham “Nottinghamia”, etc. So you could use “Needhamia”, which would then be a first declension noun.
I hope this helps, and thanks for stopping by!