هذه حديقة عامة.

• هذه = this (used with a feminine singular noun)
• حديقة = garden
• عامة = public

So the whole sentence means This is a public garden.

Because حديقة is a feminine singular noun.

In Modern Standard Arabic:

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

Since حديقة is feminine, Arabic uses هذه.

Compare:

• هذا كتاب = This is a book
• هذه حديقة = This is a garden

A big clue is the ending ـة (called taa marbuuTa / ة). This ending often marks a noun as feminine.

So:

• حديقة = feminine noun
• therefore it takes feminine agreement:
  • هذه not هذا
  • عامة not عام

That said, not every feminine noun ends in ـة, and not every noun ending in ـة behaves exactly the same in every context, but here it is a standard feminine noun.

Because adjectives in Arabic must agree with the noun they describe.

حديقة is:

• feminine
• singular
• indefinite

So عامة must also be:

• feminine
• singular
• indefinite

That is why you get:

• حديقة عامة = a public garden

and not:

• حديقة عام ❌

This agreement is a very important Arabic pattern.

Because in Arabic, adjectives usually come after the noun they describe.

So:

• حديقة عامة = literally garden public
• natural English translation: public garden

This is normal Arabic word order for noun + adjective.

More examples:

• بيت كبير = a big house
• سيارة جديدة = a new car

In Arabic, in the present tense, the verb to be is usually not expressed in simple sentences like this.

So Arabic says:

• هذه حديقة عامة

and English says:

• This is a public garden

The meaning of is is understood automatically.

This is very common in Arabic nominal sentences.

Arabic does not usually have a separate word for a / an.

Instead, indefiniteness is often shown by:

1. the absence of الـ (the), and
2. in fully vocalized Arabic, tanween on the noun/adjective.

So:

• حديقة عامة = a public garden
• الحديقة العامة = the public garden

If full case endings are written, it would be:

• حديقةٌ عامةٌ

That ـٌ helps show the phrase is indefinite.

This is a very good question, because there are two different structures that can look similar.

1. هذه حديقة عامة

This means This is a public garden.

Here, هذه stands as this, and حديقة عامة is the predicate telling you what it is.

2. هذه الحديقة العامة

This means This public garden or This is the public garden, depending on context.

Here, هذه directly points to a definite noun phrase, so the noun usually has الـ:

• الحديقة
• العامة

So the lack of الـ in your sentence is important. It helps give the meaning This is a public garden, not This public garden.

They mean different things:

هذه حديقة عامة

= This is a public garden

• حديقة عامة is indefinite
• it identifies what the thing is

هذه الحديقة عامة

= This garden is public

• الحديقة is definite: the garden / this garden
• عامة describes its quality: it is public

So Arabic changes the structure depending on whether you mean:

• This is a public garden or
• This garden is public

In Modern Standard Arabic, هذه is usually pronounced:

hādhihi

A rough breakdown:

• hā
• dhi
• hi

Some learners find it helpful to remember that it is different from هذا (hādhā).

So the full sentence in careful pronunciation is approximately:

hādhihi ḥadīqatun ʿāmmatun

In pause, many final case endings are not pronounced, so you may also hear something closer to:

hādhihi ḥadīqah ʿāmmah

A rough pronunciation is:

• حديقة = ḥadīqah
• عامة = ʿāmmah

A few pronunciation notes:

• ح is a stronger, breathier h than English h
• ع is a consonant that does not exist in English; beginners often approximate it at first
• the final ـة is often heard as -ah in pause

In very careful grammatical reading with case endings, they can be pronounced:

• ḥadīqatun
• ʿāmmatun

The fully vocalized form is:

هٰذِهِ حَدِيقَةٌ عَامَّةٌ

This shows:

• هٰذِهِ = this (feminine)
• حَدِيقَةٌ = a garden (indefinite)
• عَامَّةٌ = public (indefinite adjective agreeing with حديقة)

In normal everyday printed Arabic, these short vowels are usually omitted, so you often just see:

هذه حديقة عامة

It can have related meanings depending on context, such as public or general.

In this phrase:

• حديقة عامة

the natural meaning is public garden.

So here عامة is best understood as public, not just general.

Context usually makes the intended meaning clear.

This is a nominal sentence in Arabic.

A simple way to understand it is:

• هذه = the topic / what you are pointing at
• حديقة عامة = what you say about it

So the structure is basically:

This + [indefinite noun phrase]

meaning:

This is a public garden

This is a very common pattern in beginner Arabic, especially for identifying people or things:

• هذا بيت = This is a house
• هذه سيارة جديدة = This is a new car
• هذا مسجد كبير = This is a big mosque