Altitudinea este mare.

Because -a at the end is the definite article attached to the noun.

• altitudine = altitude
• altitudinea = the altitude

Romanian usually puts the definite article at the end of the noun, unlike English, which uses a separate word (the).

So:

• Altitudinea este mare. = The altitude is high/great.

Este means is. It is the 3rd person singular form of the verb a fi = to be.

So:

• este = is

In everyday speech, Romanians very often use the shorter form e:

• Altitudinea este mare.
• Altitudinea e mare.

Both are correct. Este sounds a little more neutral or formal; e is very common in conversation.

Yes, mare often means big or large, but it can also mean great or, in the right context, high.

With something like altitude, English normally says high, but Romanian can use mare naturally:

• altitudine mare = high altitude

So in this sentence, mare is best understood as high rather than just big.

Because mare has the same singular form for both masculine and feminine nouns.

Here, altitudinea is feminine singular, and the adjective is:

• masculine singular: mare
• feminine singular: mare
• plural: mari

Examples:

• muntele este mare = the mountain is big/high
• altitudinea este mare = the altitude is high
• munții sunt mari = the mountains are big/high

So the adjective does agree, but in the singular the form happens to stay mare.

Altitudine is a feminine noun.

You can see that in forms like:

• o altitudine = an altitude
• altitudinea = the altitude

This matters for things like articles and adjective agreement.

The normal, neutral word order is:

• Altitudinea este mare.

This is the most natural way to say it.

Romanian word order is somewhat flexible, but changing it usually adds emphasis or sounds literary:

• Mare este altitudinea. = marked, poetic, or emphatic

For a learner, it is best to stick with:

• Subject + este + adjective

A rough English-friendly pronunciation is:

• al-tee-too-DEE-nyah ES-teh MA-reh

A few helpful notes:

• ti before u here sounds like tee
• nea at the end of altitudinea sounds roughly like nyah
• e in Romanian is usually pronounced clearly, not reduced as much as in English
• r is normally tapped or rolled lightly

If you want a rough syllable breakdown:

• al-ti-tu-di-nea
• es-te
• ma-re

Normally, no. In a basic sentence like this, Romanian usually keeps the verb to be:

• Altitudinea este mare.

You would not normally say just:

• Altitudinea mare.

That would sound incomplete in standard Romanian.

So unlike some languages, Romanian generally needs the equivalent of is in this kind of sentence.

The base form is altitudine.

That is the form you would usually find in a dictionary. From that, you can build:

• altitudine = altitude
• altitudinea = the altitude
• o altitudine = an altitude

So when learning vocabulary, remember the noun itself is altitudine, and altitudinea is the definite form.

Sometimes, but not always. They are related, not identical.

• altitudine = altitude
• înălțime = height

So:

• Altitudinea este mare. = The altitude is high.
• Înălțimea este mare. = The height is great/high.

Use altitudine when you are specifically talking about altitude, especially in geography, aviation, or elevation above sea level. Use înălțime for height more generally.