Referring to Vincent’s video:
https://adckl.blogspot.com/2024/08/080924-quid-in-caelo-videre-potes-1.html
[4] 4th declension
Here are the group links to posts on the 4th and 5th
declension
https://www.facebook.com/.../permalink/470682685543005/
Nominative: arcus pluvius > accusative: Arcum pluvium
in caelō videō. │ I see a rainbow in the sky.
Nominative: tonitrus > accusative: Tonitrum in
caelō audiō. │ I hear thunder in the sky.
Nominative plural: Duo arcūs pluviī in caelō
sunt. │ There are two rainbows in the sky.
> Accusative plural: Duōs arcūs pluviōs in
caelō videō. │ I see two rainbows in the sky.
What this topic also shows is that Latin nouns can have the
same ending but belong to different declensions:
2nd declension: corvus (crow)
3rd declension: sidus (star; constellation)
4th declension: tonitrus (thunder)
Level 1: learn the meanings of the word
Moving on …
There is no way of knowing what declension
they belong to if you only know the nominative of the word. However, all the
genitive singular forms of the nouns are different which is why, when
thoroughly learning Latin nouns, you need to know both the nominative and
genitive singular because that will give you the declension; dictionaries and
textbooks will always list the nouns that way. That is particularly crucial
with 3rd declension nouns because they often undergo a change in the genitive
singular which applies to all endings added to the word:
2nd declension
corvus [nominative singular], corvī [genitive
singular]; abbreviated to corvus, -ī [2/m]
3rd declension
sidus, sideris [3/n] > Sidera in
caelō videō.
4th declension
tonitrus, tonitrūs; abbreviated to tonitrus,
-ūs [4/m]