Αυτό το βιβλίο είναι πολύ χοντρό και δεν χωράει στην τσάντα μου.

Because αυτό means this, and το is the definite article the.

In Greek, this book is normally said as:

αυτό το βιβλίο

Literally, that is closer to this the book.

This is a normal Greek pattern:

• αυτό το σπίτι = this house
• αυτή η τσάντα = this bag
• αυτό το παιδί = this child

So the article is not optional here; it usually stays with the noun.

Βιβλίο is the neuter singular form meaning book.

Greek nouns belong to grammatical genders:

• masculine
• feminine
• neuter

Το βιβλίο is a neuter noun, so words that go with it must match it in gender, number, and case.

That is why you see:

• αυτό = neuter this
• το = neuter the
• χοντρό = neuter thick

They all agree with βιβλίο.

Because the adjective has to agree with βιβλίο, which is neuter singular.

The basic forms are:

• χοντρός = masculine
• χοντρή = feminine
• χοντρό = neuter

So:

• ο χοντρός άνθρωπος = the fat/thick man
• η χοντρή τσάντα = the thick bag
• το χοντρό βιβλίο = the thick book

Here, since the noun is το βιβλίο, the correct form is χοντρό.

It can mean either, depending on context.

With a book, χοντρό means thick:

• χοντρό βιβλίο = thick book

With a person, it often means fat:

• χοντρός άντρας = fat man

So the context tells you which meaning is intended.

Here πολύ means very.

In είναι πολύ χοντρό, it modifies the adjective χοντρό:

• πολύ χοντρό = very thick

As an adverb meaning very, πολύ does not change for gender:

• πολύ καλός = very good
• πολύ καλή = very good
• πολύ καλό = very good

Be careful: πολύς / πολλή / πολύ can also be an adjective meaning much/many, and then it does change form. But in this sentence it is the adverb very.

Είναι means is and comes from the verb είμαι = to be.

So:

• Το βιβλίο είναι χοντρό = The book is thick.
• Το βιβλίο είναι πολύ χοντρό = The book is very thick.

This is a standard Greek sentence pattern: noun + είναι + adjective

The adjective after είναι is a predicate adjective, so Greek does not need an article before it.

Χωράει means fits, has room, or can go into depending on context.

So δεν χωράει στην τσάντα μου means:

• it does not fit in my bag
• there is not enough room for it in my bag

A few examples:

• Το τραπέζι δεν χωράει εδώ. = The table does not fit here.
• Όλα τα ρούχα χωράνε στη βαλίτσα. = All the clothes fit in the suitcase.

In this sentence, χωράει is referring to the book fitting inside the bag.

In Greek, δεν is the normal negation used before verbs in statements.

So:

• χωράει = it fits
• δεν χωράει = it does not fit

This is very common:

• θέλω = I want

• δεν θέλω = I do not want

• είναι μεγάλο = it is big
• δεν είναι μεγάλο = it is not big

So δεν simply goes before the verb.

Because στην is the contracted form of σε την.

Greek often combines σε + article:

• σε + την = στην
• σε + το = στο
• σε + τον = στον

So:

• στην τσάντα = in the bag / into the bag
• στο σπίτι = in the house / to the house
• στο βιβλίο = in the book / on the book, depending on context

In this sentence, στην τσάντα μου means in my bag.

Because Greek possessive weak forms like μου usually come after the noun.

So:

• η τσάντα μου = my bag
• το βιβλίο μου = my book
• ο φίλος μου = my friend

This is the normal Greek way to say possession in everyday language.

Literally, it is closer to the bag of me, but you should think of it simply as my bag.

Yes, τσάντα is feminine.

You can see this from the article in the full phrase:

• η τσάντα = the bag

And in this sentence, after σε, it appears as:

• στην τσάντα

Many Greek nouns ending in -α are feminine, though not all nouns can be guessed perfectly just from the ending. The article is the safest clue.

Yes. Both forms exist.

In everyday spoken Greek, χωράει is very common and natural. You may also see or hear χωρεί, especially in more formal style or certain fixed expressions.

So:

• Δεν χωράει στην τσάντα μου
• Δεν χωρεί στην τσάντα μου

Both can mean the same thing, but χωράει sounds more conversational.

A rough pronunciation guide is:

af-TO to vee-VLEE-o EE-ne po-LY ho-ndro ke den ho-RA-i stin TSAN-da moo

Stress falls on:

• Αυτό
• βιβλίο
• είναι
• πολύ
• χοντρό
• χωράει
• τσάντα

A few helpful notes:

• β in Modern Greek sounds like v
• χ is a throaty sound, not like English ch
• αι in είναι and χωράει sounds like e
• τσ in τσάντα sounds like ts in cats

Yes, Greek word order is somewhat flexible, though the original sentence is the most neutral and natural.

The given sentence:

• Αυτό το βιβλίο είναι πολύ χοντρό και δεν χωράει στην τσάντα μου.

You could also hear:

• Αυτό το βιβλίο δεν χωράει στην τσάντα μου, γιατί είναι πολύ χοντρό.

Greek can move parts around for emphasis, but for a learner, the original order is an excellent standard pattern:

1. topic / subject
2. είναι
   • description
3. και
4. second clause with δεν
   • verb + place phrase