Conca prope labrum olearium est.

The subject is conca.

You can tell because conca is in the nominative singular, and it is the thing that est refers to: the thing that is somewhere.

So the basic structure is:

• conca = the subject
• est = is
• prope labrum olearium = where it is

After prope, Latin normally uses the accusative case.

So in this sentence, labrum is accusative singular because it is the object of the preposition prope = near.

A very important point: labrum is a neuter noun, and in many neuter nouns the nominative singular and accusative singular look exactly the same. So even though labrum looks unchanged, here it is functioning as an accusative.

Because olearium goes with labrum and agrees with it.

In Latin, an adjective must agree with the noun it modifies in:

• gender
• number
• case

Since labrum is neuter singular accusative, olearium must also be neuter singular accusative.

So:

• labrum = neuter singular accusative
• olearium = neuter singular accusative

Olearium is an adjective modifying labrum.

It means something like of oil, for oil, or oil- depending on how the phrase is translated naturally in English.

So labrum olearium is a noun + adjective phrase, not two separate things.

Because Latin has no articles.

There is no built-in word corresponding exactly to English the or a/an in an ordinary sentence like this. Latin simply says:

• conca
• labrum olearium

and the context tells you whether English should say a basin, the basin, an oil basin, or the oil basin.

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

Putting the verb at the end is very common in Latin, especially in simple statements. So:

• Conca prope labrum olearium est.

is a perfectly normal Latin order.

English usually prefers The basin is near the oil basin, but Latin often saves the verb until the end.

Yes, often they could.

For example, Latin could also say:

• Conca est prope labrum olearium.

That would still mean essentially the same thing.

However, word order in Latin can change the emphasis. The version with est at the end sounds very natural and orderly.

Here it is a preposition.

You can tell because it is followed by a noun phrase:

• prope labrum olearium

So here prope means near and governs the accusative.

In some contexts, prope can also behave adverbially, but not in this sentence.

Because conca is not the object of prope.

The sentence is saying that the basin is located somewhere. That makes conca the subject, so it stays in the nominative.

Only the noun phrase after prope is in the accusative:

• conca = nominative subject
• labrum olearium = accusative after prope

The pattern is:

subject + prepositional phrase + verb

More specifically:

• Conca = subject
• prope labrum olearium = prepositional phrase showing location
• est = verb

So the sentence is not using a direct object. It is simply stating where something is.