Il sentiero di ghiaia è pianeggiante.

Italian uses il before most masculine singular nouns that begin with a normal consonant sound. Sentiero begins with s + vowel (se-), so the correct article is il.

You use lo before certain special sound combinations, such as:

• s
  • consonant: lo studente
• z: lo zaino
• gn: lo gnomo
• ps: lo psicologo
• x: lo xilofono

So:

• il sentiero
• but lo stradone

Di ghiaia describes what kind of path it is: a path of gravel or made of / covered with gravel.

In Italian, di + noun is often used to describe:

• material: una statua di marmo
• type: un bicchiere di plastica
• composition or surface: un sentiero di ghiaia

So sentiero di ghiaia is a very natural way to say gravel path.

Here, di does not mean possession. It is descriptive.

Because ghiaia is being used in a general, descriptive way after di.

In expressions like this, Italian often leaves out the article:

• scarpe di pelle
• tavolo di legno
• sentiero di ghiaia

Adding an article would usually make it sound more specific:

• di una ghiaia particolare
• della ghiaia che abbiamo comprato

But in the sentence given, the simple descriptive form di ghiaia is the normal choice.

Because è is the verb essere in the third-person singular: is.

The accent is important because it distinguishes è from e:

• è = is
• e = and

So:

• Il sentiero è pianeggiante = The path is level.
• Il sentiero e la strada = The path and the road.

In standard Italian, that accent should always be written.

Pianeggiante is an adjective. It describes the noun sentiero.

It means something like:

• level
• fairly flat
• not steep

It is especially common for land, roads, routes, countryside, and terrain. It sounds a bit more geographic or physical than some other options.

So in the sentence:

• Il sentiero = the subject
• è = the verb
• pianeggiante = the adjective describing the subject

Both can relate to flatness, but pianeggiante is often more natural for terrain, roads, paths, and landscapes.

A useful rough distinction is:

• piano = flat / level, often as a general adjective
• pianeggiante = fairly level, gently flat, not steep, especially for stretches of land or routes

For a path, pianeggiante sounds very idiomatic.

Also, piano has many other meanings in Italian, such as:

• softly: parla piano
• floor/story of a building: primo piano
• plan: un piano

So pianeggiante is a more precise choice here.

Because not all Italian adjectives use the -o / -a pattern.

Pianeggiante belongs to a group of adjectives that usually have:

• one form for masculine singular and feminine singular: pianeggiante
• one form for masculine plural and feminine plural: pianeggianti

So you get:

• il sentiero pianeggiante
• la strada pianeggiante
• i sentieri pianeggianti
• le strade pianeggianti

Even though sentiero is masculine singular, pianeggiante is already the correct singular form.

Yes. Italian adjectives normally agree with the noun they describe in gender and number.

Here:

• sentiero is masculine singular
• pianeggiante is singular

With this adjective, the singular form is the same for masculine and feminine, so you do not see a gender change in the ending.

You only see a change in the plural:

• singular: pianeggiante
• plural: pianeggianti

Yes, that is grammatically possible, but it is slightly different in focus.

• Il sentiero di ghiaia è pianeggiante = The gravel path is level.

  • Here di ghiaia is part of the noun phrase the gravel path.

• Il sentiero è di ghiaia = The path is made of gravel.

  • Here the sentence is specifically telling you what the path is made of.

So both are correct, but they organize the information differently.

Yes. It follows the very common pattern:

article + noun + description + verb + adjective

More simply:

• Il sentiero di ghiaia = subject
• è = verb
• pianeggiante = complement/adjective

This is the neutral, natural order for a basic statement.

You could change the order for emphasis, but the given version is the standard one.

Ghiaia is pronounced roughly like GYAH-yah.

A few helpful points:

• gh before i or e keeps the hard g sound
• so ghi- sounds like ghee / gya, not like English giant
• the word has stress on the first syllable: GHIA-ia

So:

• ghiaia ≈ GYAH-yah

That gh spelling is very common in Italian:

• spaghetti
• laghi
• Margherita