I believe there are no exceptions to this rule. That's what I have always read, and I have never encountered any, neither in Greek nor in Latin, nor even in German.
There is an hypothesis about the cause of this phenomenon. Neuter words were historically limited to inanimate objects or things that cannot act. In a basic sentence, it was rarely or never the ...
This means "illa" definitely doesn't refer to "dies".
But it does!
The word dies can be feminine, and it is here.
The feminine gender is rarer but it is the typical choice for a special day like an appointment or a deadline.
That's why it was chosen here.
For details, see this question about gender variation in dies.
These are the exact same word, and yes both mean "world" but no you cannot substitute them for each other. Latin is a fully inflexional language, which means that the words have endings which change depending on their grammatical use. You can compare mundum and mundi to whom and whose. You wouldn't say, "This is me ball" (well, not in Standard English, at ...
I believe there's no straightforward answer as to „why different usage contexts correlate to different grammatical gender“, but the etymological origin gives some insights to the gender.
Diēs comes from Proto-Indo-European *d(i)jéus „daytime sky, Sky-god“ and is cognate to Iūp-piter (≈ Diespiter, „dies pater“), so originally it should have been masculine, ...
I searched for the vocative form Gnaee in several corpora but did not find any results. A general web search seems to reveal only automatically generated vocatives, which I would not lend much credence to, as well as the excellent 16th century example cited by @JoelDerfner in Juan Luis Vives's De Initiis Sectis Et Laudibus Philosophiae. The two alternatives ...
It's pretty much arbitrary.
There are some standard patterns: first-declension nouns tend to be feminine, second-declension masculine/neuter, third-declension abstract concepts, fourth-declension collectives and states, fifth-declension feminine. But there's an exception to each and every one of these rules.
Historically speaking, the declensions derived ...
Sebastian Koppehel said the important bits but I want to provide some background for people who like that sort of thing (me). Don't let this confuse you if you don't find it helpful—it can be a lot when you just want to focus on learning Classical Latin.
The future participle of vincō being vīctūrus, while not synchronically regular in Latin, is unsurprising:...
There are two (main) classes of adjectives in Latin:
Some adjectives use the first declension for feminines (e.g. Romana, "Roman") and the second declension for masculines and neuters (e.g. Romanus and Romanum).
For adjectives like this masculine forms look different from feminine forms — with the exception of plural dative and ablative.
The phrase you quote has words in the vocative case.
Domine Fili unigenite Jesu Christe
The vocative case is used for address. That is,
O Lord, only begotten son, Jesus Christ
The particle O underscores this fact, that the phrase is in the form of address.
On the other hand, Iesus is in the nominative case. The nominative case is used for the subject of ...
It is of the first declension, but not of the most typical kind.
I would divide the first declension into four classes:
The last ...
If you look up vivo and vinco in a dictionary, you will see that both have the same supine stem: victum. Thus they share not only the future participle, but also the two supines and the perfect participle. It is my subjective impression that victurus, when you actually encounter it, is usually a form of vivo, whereas the perfect participle victus from vivo ...
'Why' isn't usually a good question for these types of things, because the answer is often "just because." The Greek isn't typical, but it does have a parallel with o-contracted words like νοῦς, περίπλους, or (neuter) κανοῦν.
Nominative Ἰησοῦς νοῦς
Genitive Ἰησοῦ νοῦ
Dative Ἰησοῖ/Ἰησοῦ νῷ
Accusative Ἰησοῦν νοῦν
In a recent paper (included in The Latin of the Grammarians), I have made the point that Latin grammarians, unlike their Greek predecessors, did not expressly stress the uninflectional nature of adverbs, and this may be due to the fact that they observed some sort of declension in some types of adverbs (not only those derived of adjectives -doctus > docte-, ...
I can only partially answer your question. In medieval documents dies is sometimes feminine where based on classical usage we would expect it to be masculine. Examples:
Liber Pontificalis1 (~10th century) 371, in reference to Charlemagne's arrival in Rome (but note that this text contains frequent grammatical irregularities):
Et alia die, secundum ...
To answer your second question, this rule is completely exceptionless, not only in Latin but in all Indo-European languages (that is, those that have a neuter gender at all).
neuter gender always had identical nominative, accusative and vocative forms in all three numbers
Archaic Syntax in Indo-European
This is a really common stumbling block for those approaching Latin from the background of a language like English, so it merits a careful step-by-step explanation. I'll break my response into two steps:
Adjectives agree in case, number, and gender with the noun they modify.
Suus, -a, -um is an adjective.
Adjectives agree with their nouns
Let's start by ...
A number of Greek names ending in -ō have both Latin and Greek style declensions.
One would indeed expect the typical Latin form Ionem, but Io is valid as well.
The context is fortunately clear enough so that we can be confident that Io is ...
I'm not sure there is more of a "why" to it than the fact that, in Latin, the ablative mostly absorbed the Proto-Indo-European instrumental's functions as the latter disappeared, just as the Greek dative did (which also happened to absorb some functions of the Proto-Indo-European ablative as it disappeared in Greek). Some other functions of the ablative were ...
The Latin word used for "world" here is mundus.
This word has several forms (singular/plural):
The five grammatical cases are used in different contexts and they are rarely interchangeable.
"Of the world" requires ...
To complete your example, it would be,
Quid est hoc? What is this?
Because "what" is neuter, whereas "who" could be masculine or feminine.
The demonstratives (hic, ille, iste, and is) can be used as either pronouns or adjectives. You can read about their paradigms on section 146 of Allen and Greenough, and their uses on section 296.
According to this study, the distribution is as follows:
1st declension 21.6%
2nd declension 23.7%
3rd declension 52.6%
4th declension 1.4%
5th declension 0.7%
("Development of Gender Classifications: Modeling the Historical Change from Latin to French," by Maria Polinsky and Ezra Van Everbroeck Language Vol. 79, No. 2, Jun., 2003, Table 2, pg. 362)
It is the feminine nominative and refers to dies. It means “that day.”
You do not say why you think you can definitely rule it out, but I guess you think dies is masculine, which is indeed the case. But it is also often feminine. Generally speaking, it is feminine only when referring to a set day, an appointed time. This does arguably apply to the day of ...
Dōnum is neuter; amīcus, fīlius, and ager are masculine. Neuter nouns are always the same in both the nominative and accusative case, in both singular and plural. See this question for more about how universal this is.
Here are some more neuter nouns that you may be familiar with (from early chapters in Lingua Latina Per Se Illustrata):
Baculum dominī in ...
It is not an ordering, but it is common in the context of historical linguistics or comparative Indo-European linguistics to categorize nouns by the ending element of the stem:
first declension is ā-stem nouns*
second declension is o-stem nouns
third declension is consonant-stem and i-stem nouns (consonant stems can be divided into t-stems, c-stems etc.)
For unfamiliar words, it never hurts to check the dictionary. Here is what Lewis and Short have:
Īō, Iūs, and Īōn , Iōnis, f., = Ἰώ, I.a daughter of Inachus, king of Argos, beloved by Jupiter, and changed, through fear of Juno, into a cow; afterwards worshipped as an Egyptian deity, under the name of Isis. —Form Io, Ov. H. 14, 85; Prop. 2, 28 (3, 24), 17; ...
Short answer: Latin does not allow the sequence ts (except in compound words), so an expected form like monts was remade into mons.
Of course, this only leads to the further question of why this sequence was disallowed in Latin, which is much more difficult to answer. Every language has a set of preferences as to which sequences of sounds it does and doesn'...
Ancient Latin had no separate letter for the the vowel I and the consonant Y (J in German). They were both written as I. In Medieval Latin, though, a development took place that differentiated between the vowel I (written as I, i) and the consonant I (now written as J, j).
There is no difference, then, between Iesus and Jesus in Latin.
Jesu/Iesu, though, ...
Regarding why the Latin text uses the accusative and then the nominative, this is simply because the Vulgate is closely following the Greek original:
6 ὃς ἀποδώσει ἑκάστῳ κατὰ τὰ ἔργα αὐτοῦ·
7 τοῖς μὲν καθ’ ὑπομονὴν ἔργου ἀγαθοῦ δόξαν καὶ τιμὴν καὶ ἀφθαρσίαν ζητοῦσιν ζωὴν αἰώνιον·
8 τοῖς δὲ ἐξ ἐριθείας καὶ ἀπειθοῦσι τῇ ἀληθείᾳ πειθομένοις δὲ τῇ ἀδικίᾳ ὀργὴ ...