Cavea plena est.

Cavea is nominative singular.

You can tell because it is the subject of the sentence: the arena / enclosure / seating area is full. In Latin, the subject is normally in the nominative case.

Also, cavea is a first-declension noun, and its nominative singular form often ends in -a.

Because plena has to agree with cavea.

The adjective comes from plenus, plena, plenum = full. Since cavea is:

• feminine
• singular
• nominative

the adjective must also be:

• feminine
• singular
• nominative

So:

• masculine: plenus
• feminine: plena
• neuter: plenum

Here, plena is the correct form.

It is an adjective here.

More specifically, it is a predicate adjective: it describes the subject after a form of to be.

So the structure is:

• cavea = subject
• plena = adjective describing the subject
• est = is

In other words, plena is not being used as a separate noun; it is saying what cavea is like.

Est is the third person singular present of sum, meaning is.

So Cavea plena est literally means:

• The arena is full
• or The enclosure is full

Latin often uses sum just like English uses to be in sentences with predicate adjectives.

Yes, sometimes Latin can omit a form of sum, especially in poetry or in certain styles of prose, if the meaning is clear.

So Cavea plena could sometimes be understood as The arena is full.

However, for learners, and in straightforward prose, Cavea plena est is the clearest full sentence.

Because Latin does not have articles like English.

So cavea can mean:

• a cavea
• the cavea
• sometimes just cavea in a general sense

You figure out whether English should use a, an, or the from the context.

That is why Cavea plena est can be translated as The arena is full or An arena is full, depending on context, though in normal English the is often the most natural.

No. After sum (to be), Latin does not use the accusative for a predicate adjective.

In this sentence:

• cavea is the subject, so it is nominative
• plena describes the subject, so it also stays nominative

This is different from a sentence with a direct object. There is no direct object here.

So:

• Cavea plena est = The arena is full
• not something like Caveam plenam est, which would be incorrect here

Yes. Latin word order is much more flexible than English word order.

You could also see:

• Plena est cavea
• Cavea est plena
• Est cavea plena

All of these can mean essentially the same thing: The arena is full.

The endings show the grammar, so Latin does not rely on word order as heavily as English does. Different word orders can add different emphasis, but the basic meaning remains the same.

It comes from the adjective plenus, plena, plenum.

That is how Latin adjectives are usually listed in dictionaries: the masculine, feminine, and neuter nominative singular forms.

So if you look up plena, you should expect to find it under plenus.

Latin can add what the thing is full of. With plenus, Latin commonly uses either a genitive or an ablative, depending on the word and style.

For example:

• Cavea spectatorum plena est = The arena is full of spectators
• Cavea spectatoribus plena est can also occur

At a beginner level, the important idea is that plenus can take an added word meaning of something. But in Cavea plena est, nothing is added, so it simply means The arena is full.

In a basic Classical pronunciation, approximately:

KA-weh-a PLAY-na est

A few helpful points:

• c is always hard, like k
• v is pronounced like w
• ae is like the ai in aisle or a similar diphthong
• plena has a long e sound in Classical Latin

So cavea is not pronounced like English cave. It is more like ka-weh-a.