The Third Declension

The third declension is the big one

The first declension was brought to you by the letter "a," which was usually visible. The second was sponsored by the letter "o," which was not. The "o" was absorbed by the endings except in things like puero or puerorum. The other 21 letters give you the third declension, which gives an idea of its importance. Some people assert that the letter "u" gives the fourth declension, and "e" the fifth, but this is superfluous for our purposes. For us, these will be just special cases of the third declension, as they really are.

laus, laudis (f)
case singular plural
nom laus laudes
gen laudis laudum
dat laudi laudibus
acc laudem laudes
abl laude laudibus
You've already seen the word laus (praise) in the case laude (ablative). It is a habit of the third declension for the real stem not to be obvious in the nominative singular, but to appear in the genitive and everywhere else. So we usually remember a word as, for example, laus, laudis so we know the stem. Your job is only to recognize a case, not form it, and you will find this easy. Laus is declined in the table. What does laus Deo mean?

Decline fraus, fraudis (fraud, feminine) We have already used pumex, pumicis (pumice) which happens to be hermaphroditic - you can make it either masculine or feminine. Canis, canis (dog) can also be masculine or feminine; it depends on the dog.

The nominative singular typically ends in s, often in the form of x. The -um is genitive plural (compare -arum and -orum), and the very memorable -ibus is dative and ablative plural. Decline pes, pedis (foot). This gives us the useful case pedibus, meaning on or by foot. When somebody asks you how you came, reply in Latin: pedibus! The ablative case by itself, without any preposition, tells how or with what something was done. How would you say: the man kills the bear with a knife? Answer: vir ursum cultro necit. The fact that culter is there in the ablative says that it was used for the deed.

One very useful class of feminine nouns ends in -io, -ionis. For example, natio, nationis (birth). This is a special case of nouns ending in -o, which are masculine unless they end in -io, -do, or -go, however: try leo, leonis (lion), or homo, hominis (human being), which are masculine. Homo does't mean a male specifically; it is used when sex is not an issue. Mulier, mulieris (f) is the feminine counterpart of vir, viri, which do mean "woman" and "man". There are many variations and exceptions in the third declension, but recognition of the case is usually not too difficult. For example, titio, titionis (firebrand) is masculine, not feminine as you might expect. You might find this word amusing to use.

mare, maris (n)
case singular plural
nom mare maria
gen maris marum
dat mari maribus
acc mare maria
abl mari maribus
Remembering that neuter nouns are the same in nominative and accusative, and that the nominative plural ends in -a, decline nomen, nominis (name). Opus, operis (work) is another neuter. The ending -us is often third or fourth declension, not second; this is why you have to recall the genitive. Opera, -ae (f) means pains, effort, exertion, work, leisure, help, workman. Operae (plural) can be a gang or a hired mob. This is the kind of opera you go to, not an opus. An onus, oneris is a load or burden, and has become an English word. The word mare, maris (sea) is declined as in the table. Note that the genitive plural is not marium, though the ablative singular is mari. Actually, the genitive plural is found in only one place in poetry, where the -i- may have been omitted just to suit the metre. Poets are allowed to do things like this. If you have a need for the word, you might as well use the regular marium, as Romans probably did.

There is a rule, not a very strict one, that nouns with the same number of syllables in nominative and genitive have -ium in the genitive plural, while those that have an additional syllable in the genitive have -um. collis, collis (m, hill), for example, has collium. canis, canis (m, dog), panis, panis (m, bread), however, have -um. animal, animalis (n, living being) is just like mare, except that it has -ium. Confusing? Sometimes even Romans didn't know whether to use -um or -ium! All these nouns can be considered as having a stem ending in -i, which is why "i" is so popular with them. Note also that the ablative singular ends in -i, not -e, for such nouns. The nouns in -is, -is, which are numerous, are never neuter.

felix, felix
singular plural
case m & f neut m & f neut
nom felix felix felices felicia
gen felicis felicis felicium felicium
dat felici felici felicibus felicibus
acc felicem felix felices felicia
abl felici felici felicibus felicibus
This new class of endings can be applied to adjectives, as well. Happily, the masculine and feminine endings are the same (there is no alternative!), and the neuter only differs in the nominative and accusative. Take felix, felix as an example. Its declension is shown in the table. It is called an adjective of one ending. Note that an extra i has sneaked in here and there (this is an -i- stem), but there are really not very many different forms. See if you can decline fidelis, fidele (faithful). There is no sneaky i in fidelis,which is an adjective of two endings.

Try to express latine (ablative; "with latin"): the happy (felix) farmer loves the faithful (fidelis) dog. This is: tama menac meledif aliocirga xileF. The Latin is written backwards so you have a chance to make up a sentence without being prompted by the answer.

As they give rise to different declensions in nouns, different stem vowels give rise to different conjugations in verbs. The long e gives us the second conjugation, which is just like the first. Examples are timeo (fear), teneo (hold), habeo (have), video (see), maneo (remain, stay), moveo (move), debeo (owe), doleo (grieve, suffer), terreo (frighten), augeo (increase), doceo (teach) and moneo (warn). Note how many cognates you can find in English to help you remember these verbs! They go timeo, times, timet, etc. They all have infinitives ending in -ere where the first e is long, and remains as a short e when the endings are added. They are conjugated like the first conjugation. This is not a very big bunch of words, but it's convenient to introduce them here. Write: the small farmer fears the large bear. musru mungam temit alocriga suvraP. Backwards Latin is easy to say, it seems!

Habeo and teneo both mean "have, hold", but the first is more figurative, the latter more concrete. Habeo is not a helping verb in Latin that can make past tenses when combined with the past participle, nor does it imply necessity or compulsion. There are better ways to say both these things. In Spanish, teneo has come to mean "have, hold" while habeo is used exclusively as a helping verb, and no longer means to have or hold. In English, "to have" is used in both ways.

Here is a quote from Terence, the early poet and playwright: auribus teneo lupum. You may be able to figure this one out with no help; it's not because its so easy, it's because you are already learning some Latin. Auris, auris (f) is ear, of course. What does the case imply?

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Composed by J. B. Calvert
Created 24 June 1999
Last revised 2 January 2005