النادي في المدينة.

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

So:

• النادي = the club
• في المدينة = in the city

Together, Arabic naturally understands this as:

• The club is in the city

This kind of sentence is called a nominal sentence in Arabic.

الـ is the Arabic definite article, meaning the.

So:

• نادي = a club / club
• النادي = the club
• مدينة = a city / city
• المدينة = the city

In this sentence, both nouns are definite:

• النادي = the club
• المدينة = the city

Because the sentence is talking about a specific club and a specific city.

Arabic often uses definiteness the same way English does here:

• النادي في المدينة = The club is in the city

If you changed one or both nouns, the meaning would change:

• نادٍ في المدينة = a club in the city
• النادي في مدينة = the club is in a city

So the الـ on both words matters.

في is a preposition meaning in.

So:

• في المدينة = in the city

It is one of the most common Arabic prepositions.

النادي is pronounced an-nādī, not al-nādī.

That is because ن is a sun letter. With sun letters, the ل of الـ is not pronounced, and the next consonant is doubled.

So:

• النادي → pronounced an-nādī

By contrast, in المدينة, the م is a moon letter, so the ل is pronounced:

• المدينة → al-madīna

The fully vocalized sentence is:

النَّادِيُ فِي الْمَدِينَةِ

This shows the grammatical endings:

• الناديُ = nominative
• المدينةِ = genitive, because it comes after في

In normal Arabic writing, these short vowel endings are usually omitted, so you usually just see:

النادي في المدينة

Because it comes after the preposition في.

In Arabic, prepositions like في, من, على, إلى normally make the following noun genitive.

So:

• في المدينةِ = in the city

Even if the ending is not written in normal text, the grammar is still there.

This is a nominal sentence made of:

• النادي = the topic / subject
• في المدينة = a prepositional phrase giving information about it

So the basic structure is:

• [noun] + [prepositional phrase]

Literally:

• The club — in the city

Natural English:

• The club is in the city

Yes, مدينة is a feminine noun. You can often tell because it ends in ـة.

So:

• مدينة = city (feminine)
• المدينة = the city

In this sentence, that does not change anything important, because there is no adjective or verb that has to agree with it. But if you added an adjective, the adjective would need to match in gender and definiteness.

For example:

• المدينة الكبيرة = the big city

The final ـة is called tāʾ marbūṭa.

At the end of a word, when pausing, it is usually pronounced like -a:

• مدينة → madīna

But in some grammatical contexts, especially when followed closely by another word in a phrase, it can sound like t.

In this sentence by itself, you would normally hear:

• al-madīna

Usually, المدينة most directly means the city.

So the clearest meaning is:

• The club is in the city

Depending on context, English might translate this more naturally as in town, but that would be an interpretation from context, not the most literal meaning of the Arabic words themselves.