هذا جزء من الكتاب.

In Arabic, the present tense of to be is usually not written or said in simple sentences like this.

So:

• هذا جزء من الكتاب
• literally: this part from the-book
• natural English: This is part of the book

This kind of sentence is called a nominal sentence in Arabic. The meaning of is is understood automatically.

If you wanted was, then Arabic would use a verb, for example:

• كان هذا جزءًا من الكتاب = This was part of the book

Because جزء is a masculine singular noun.

In Arabic, the demonstrative must match the noun in gender and number:

• هذا = this for masculine singular
• هذه = this for feminine singular

So:

• هذا جزء = this is a part
• but with a feminine noun, for example:
  • هذه صفحة = this is a page

Even though the English word part has no grammatical gender, the Arabic noun جزء is grammatically masculine.

جزء means part, portion, or section, depending on context.

It is usually pronounced approximately as:

• juz’
• more fully in careful MSA pronunciation: juzʾ

The last symbol ء is the hamza, a glottal stop. That means the word ends with a little catch in the throat, somewhat like the break in uh-oh.

So the word is not just juz. The final hamza matters.

Because Arabic commonly expresses part of something with:

• جزء من ... = part of ...

So:

• جزء من الكتاب = part of the book
• جزء من الدرس = part of the lesson
• جزء من المشكلة = part of the problem

Here, من literally often means from, but in many contexts it is used where English says of.

Because الكتاب means the book, while كتاب means a book.

So:

• هذا جزء من الكتاب = This is part of the book
• هذا جزء من كتاب = This is part of a book

The definite article الـ works like English the.

Yes. من is a preposition, and nouns after prepositions are in the genitive case.

In fully vocalized Arabic, you would write:

• هذا جزءٌ من الكتابِ

Notice:

• جزءٌ ends in -un because it is the predicate of the sentence
• الكتابِ ends in -i because it comes after من

In normal everyday Arabic writing, these short vowels are usually not written, so you normally see:

• هذا جزء من الكتاب

Not directly. This is not a simple iḍāfa like بابُ البيتِ (the door of the house).

Instead, it is:

• جزء
  • من
    • الكتاب

That means it is a noun followed by a prepositional phrase.

Arabic often prefers جزء من... for the meaning part of....

A learner might wonder about جزء الكتاب. That form can exist in some contexts, but جزء من الكتاب is the normal and clear way to say part of the book.

It is a nominal sentence:

• هذا = the topic / subject-like element
• جزء من الكتاب = the predicate / comment about it

So the structure is basically:

• هذا = this
• جزء من الكتاب = part of the book

Together: This is part of the book.

You can think of it as:

• [This] [part of the book]

with is understood.

In normal Arabic writing, short vowels are usually omitted.

So the fully vocalized form would be:

• هٰذا جُزْءٌ مِنَ الكِتابِ

But most of the time you will only see:

• هذا جزء من الكتاب

A learner should know that the hidden endings are roughly:

• هذا = hādhā
• جزءٌ = juzʾun
• منَ = mina
• الكتابِ = al-kitābi

In pause, many speakers also simplify the pronunciation of case endings in actual speech.

Because Arabic often starts this kind of sentence with the demonstrative:

• هذا جزء من الكتاب = This is part of the book

This is a very common pattern:

• هذا كتاب = This is a book
• هذا درس مهم = This is an important lesson
• هذه سيارة جديدة = This is a new car

So هذا introduces the thing being pointed out or identified.

Usually, no. The most natural reading is:

• This is part of the book

That is because هذا is functioning as this, not this part.

If you wanted to say This part is from the book, Arabic would more naturally say something like:

• هذا الجزء من الكتاب
• or another sentence depending on the exact context

So in your sentence, هذا points to something, and جزء من الكتاب tells you what it is.

Arabic often does not make a strong distinction here. The same sentence:

• هذا جزء من الكتاب

can work for both:

• This is a part of the book
• This is part of the book

English sometimes includes a, but Arabic does not have an indefinite article like a/an. Indefiniteness is usually shown simply by the noun having no ال.

So جزء by itself is indefinite: a part / part.

Yes, depending on what you want to say.

For example:

• هذه جزء من الكتاب would be wrong with جزء, because جزء is masculine
• ذلك جزء من الكتاب = That is part of the book
• هذا جزء مهم من الكتاب = This is an important part of the book

So the choice of demonstrative depends on gender, number, and sometimes distance.

In careful MSA with case endings, it would be approximately:

• hādhā juzʾun mina al-kitābi

Often, because of normal pronunciation habits, you may hear something closer to:

• hādhā juzʾ min al-kitāb
• or hādhā juzʾun mina l-kitābi

A simple learner-friendly pronunciation is:

• haa-thaa juz’ min al-kitaab

The most important things to notice are:

• هذا = hādhā
• جزء ends with a hamza
• الكتاب = al-kitāb