Compartimentul ascunde magnetul.

Because -ul is the Romanian definite article for many masculine and neuter singular nouns.

So:

• compartiment = compartment
• compartimentul = the compartment
• magnet = magnet
• magnetul = the magnet

Unlike English, Romanian usually puts the at the end of the noun instead of using a separate word before it.

Romanian normally uses an attached definite article, not a separate word like English the.

So English:

• the compartment
• the magnet

becomes Romanian:

• compartimentul
• magnetul

This is one of the first big differences English speakers notice in Romanian grammar.

Ascunde comes from the verb a ascunde, meaning:

• to hide
• to conceal

In this sentence, ascunde means hides.

So Compartimentul ascunde magnetul means The compartment hides the magnet.

Depending on context, ascunde can also sound like conceals in more formal English.

Ascunde is the 3rd person singular present tense form of a ascunde.

That means it is used with:

• el = he
• ea = she
• compartimentul = the compartment
• any other singular noun acting as he/she/it

Examples:

• El ascunde magnetul. = He hides the magnet.
• Ea ascunde magnetul. = She hides the magnet.
• Compartimentul ascunde magnetul. = The compartment hides the magnet.

It can mean either, depending on context.

Romanian present tense often covers both:

• hides
• is hiding

So Compartimentul ascunde magnetul could mean:

• The compartment hides the magnet
• The compartment is hiding the magnet

In many learning examples, the simple English present hides is the most direct translation.

In this sentence, the most natural reading is:

• Compartimentul = subject = the thing doing the action
• ascunde = verb
• magnetul = direct object = the thing being hidden

So:

• The compartment hides the magnet

Romanian often uses the same Subject–Verb–Object order as English, especially in simple sentences like this one.

Also, semantically, it makes sense that a compartment could hide a magnet.

Yes. Romanian word order is fairly flexible, although Subject–Verb–Object is the most neutral pattern.

The normal version is:

• Compartimentul ascunde magnetul.

But Romanian can sometimes move words around for emphasis, for example:

• Magnetul îl ascunde compartimentul.

That would sound more marked and would usually need extra context. For a learner, the original sentence is the straightforward neutral order.

Because magnetul is a direct object, but Romanian usually uses pe mainly with people or other highly specific/animate direct objects.

For example:

• Văd băiatul. / Îl văd pe băiat. = I see the boy.

But with an inanimate object like magnetul, you normally do not use pe:

• ascunde magnetul = hides the magnet

So the sentence is correct exactly as written.

Both are typically treated as neuter nouns in Romanian.

A useful thing to know about Romanian neuter nouns is that they behave:

• like masculine in the singular
• like feminine in the plural

That is why in the singular you get forms like:

• compartimentul
• magnetul

For this sentence, the important practical point is simply that both nouns take -ul in the singular definite form.

That would be:

• Un compartiment ascunde un magnet.

Here:

• un compartiment = a compartment
• un magnet = a magnet

So compare:

• Compartimentul ascunde magnetul. = The compartment hides the magnet.
• Un compartiment ascunde un magnet. = A compartment hides a magnet.

Here are the combinations:

• Compartimentul ascunde un magnet. = The compartment hides a magnet.
• Un compartiment ascunde magnetul. = A compartment hides the magnet.

This is a good way to see how Romanian marks definiteness directly on the noun.

A rough English-friendly guide is:

• com-par-ti-MEN-tul as-CUN-de mag-NE-tul

A few helpful points:

• c in compartimentul is a hard k sound
• sc in ascunde sounds like sk
• g in magnetul is a hard g sound, as in go
• ul at the end is pronounced, not silent

This is only an approximation, but it will get you fairly close.

Yes. It is a clear cognate.

• compartiment = compartment
• magnet = magnet

That makes the vocabulary easier for an English speaker, even though the grammar is different because Romanian adds the article to the end of the noun.

Yes, you could.

• Compartimentul ascunde magnetul. = The compartment hides the magnet.
• Compartimentul ascunde magnetul. = The compartment conceals the magnet.

Hides is the more everyday translation.
Conceals is a bit more formal or deliberate in tone.

Usually not, if the subject is already clear.

In this sentence, the subject is explicitly stated:

• Compartimentul = the compartment

So there is no need to add a pronoun.

Romanian often omits subject pronouns because the verb form already gives information about the person and number. Here, though, the noun itself tells you the subject, so the sentence is complete as it is.