Botanical Latin
 Lesson 10 - Fourth Declension Nouns


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(updated 11 February 2023)

In this lesson you will learn the fourth declension. The diagnostic genitive singular ending for fourth declension nouns is “-ūs”.

To form the fourth declension, drop the -ūs ending from the genitive singular—this gives the stem—and add the fourth declension endings (given in tables 10.1 and 10.2 below). For example, the genitive singular of the Latin word for fruit is fructūs. Drop the -ūs and you have the stem fruct-.


Table 10.1 - fourth declension endings for masculine and feminine nouns
case singular plural
nominative stem + us stem + ūs
genitive stem + ūs stem + uum
dative stem + uī stem + ibus
accusative stem + um stem + ūs
ablative stem + ū stem + ibus


Table 10.2 - (masculine) example: fructus, fructu (fruit; without macrons) fourth declension endings for masculine and feminine nouns
case singular plural
nominative fructus fructus
genitive fructus fructuum
dative fructui fructibus
accusative fructum fructus
ablative fructu fructibus


Table 10.3 - fourth declension endings for neuter nouns
case singular plural
nominative stem + ū stem + ua
genitive stem + ūs stem + uum
dative stem + ū stem + ibus
accusative stem + ū stem + ua
ablative stem + ū stem + ibus


Table 10.4 - (neuter) example: cornu, cornus (horn; without macrons)
case singular plural
nominative cornu cornua
genitive cornus cornuum
dative cornu cornibus
accusative cornu cornua
ablative cornu cornibus


There are relatively few fouth declensions nouns in botanical Latin, as is also true in classical Latin, and most are masculine.

Vocabulary
fructus (m) - fruit
 sinus (m) - sinus
 tribus (f) - tribe


Latin Descriptions and Diagnoses -


Exercises
Translate the following into English.
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Write the following in Latin.
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Write a Latin description for the following. These are more challenging. You have to convey the meaning rather than following the exact wording.
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