How To Find the Base of Any Latin Noun (Easily!)
You need to know the base or stem of a Latin noun in order to be able to decline it. In this post you will learn how to find the base of any Latin noun!
First, let’s review what a base is.
The base is the part of a Latin 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 of a few second declension nouns).
The base is also what allows you to identify the word and establish its meaning. So being able to determine a noun’s base is crucial.
Some people call this the stem instead of the base. But don’t worry – the process of finding the stem/base is the same, no matter what you call it.
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How to find the base of a Latin noun
Finding the base of a Latin noun is quite simple. All you need to do is look at the noun’s genitive singular and remove its case ending. Whatever you have left is the base.
Here are the genitive singular endings for the five Latin noun declensions:
| Declension | Genitive Singular |
|---|---|
| First | -ae |
| Second | -ī |
| Third | -is |
| Fourth | -ūs |
| Fifth | -eī / ēī |
When you see the genitive singular of a noun, remove the ending and you will have the base. You also use the genitive singular to find a noun’s declension, so it is an important form to know.
Now let’s look at an example.
NOTE: Latin dictionaries and textbooks present nouns in a specific format: the nominative singular followed by the genitive singular.
This means that, when you see a noun listed in dictionary form, you should look at the second word to determine the base.
Question: What is the base of mater, matris?
Answer: This is a third declension noun, as we can see from the –is ending on the genitive singular. So, to find the base, we remove the –is.
matris – is = matr-This means that our base is matr-!
Now it’s your turn to practice. What is the base (or 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 base of a Latin noun from the nominative?
You may have noticed that, in most of the words above, the base was also present in the nominative singular. So 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 base of mōns is mont– and the base of iter is itiner-.
In these two cases, the base is NOT present in the nominative. So we really do need to know the genitive in order to find the bases 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 base because this ALWAYS works. No exceptions.
PRO TIP: Be extra careful with third declension nouns. Their bases can be weird and unpredictable.
What if the dictionary doesn’t give the full genitive singular?
Most beginning Latin textbooks will give you the full nominative and genitive singular for each noun. But since first, second, fourth, and fifth declension bases are very regular, often dictionaries use shorthand.
FIRST DECLENSION: sella, sellae becomes sella, ae. When this happens, to get the base 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 usually include the full genitive singular.
More Practice With 3rd Declension Nouns
Since 3rd declension bases can be so weird, let’s do another quick exercise. Find the bases 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–
How are you feeling? Is everything making sense so far? We just have one more topic to address, and then you will know how to find the base of any Latin noun.
How to Find the Base 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 base. 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.
| Declension | Nom. Pl. | Gen. Pl. |
|---|---|---|
| 1st | -ae | -ārum |
| 2nd (masc.) | -ī | -ōrum |
| 2nd (neut.) | -a | -ōrum |
| 3rd (masc./fem.) | -ēs | -um / ium |
| 3rd (neut.) | -a/ia | -um/ium |
| 4th (masc.) | -ūs | -uum |
| 4th (neut.) | -ua | -uum |
| 5th | -ēs | -ērum |
Practice identifying the bases 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–
Final Thoughts on Latin Noun Bases
Now you know how to find the base of any Latin noun. This means that, by extension, you have the fundamental knowledge needed to decline any Latin noun.
Remember: the base is the portion of the noun to which case endings are added. To decline a noun, then, you 1) find the base and 2) add the proper case endings to it.
Latin noun endings vary based on declension, so it is crucial to know a particular noun’s declension before you start adding endings. Sometimes the noun’s gender is relevant, too. But the first step in declining a noun is always to identify its base.
One last thing. I mentioned at the beginning of the post that some people will use the word “stem” interchangeably with “base”. Technically, however, a Latin noun’s stem refers to its base plus a stem vowel.
This is why I choose to use the more precise term “base” in this post. But stem is everywhere in Latin classrooms, and I myself have often used “stem” with my students in the past.
If you are interested in grammatical terminology, you can read more about bases, stems, and roots in sections 24-28 of my favorite Latin grammar. But all you really need to know to be successful in Latin is how to find the base and which endings to add to it!
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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!