إنذار الحريق قرب كاشف الدخان.

This is very common in Arabic, especially on signs, labels, maps, and notices.

The phrase is not a full everyday sentence like The fire alarm is near the smoke detector. It is more like a sign-style label:

• Fire alarm near the smoke detector

Arabic often omits words like is, there is, or other linking elements when the meaning is obvious from context.

A fuller sentence could be:

• إنذارُ الحريقِ قريبٌ من كاشفِ الدخانِ = The fire alarm is near the smoke detector
• يوجدُ إنذارُ الحريقِ قربَ كاشفِ الدخانِ = There is a fire alarm near the smoke detector

So the short version is normal in practical written Arabic.

They form an iḍāfa construction, often called a genitive construction or noun + noun possessive phrase.

So:

• إنذار الحريق = fire alarm
• literally: alarm of the fire

In Arabic, iḍāfa often expresses relationships that English expresses with:

• of
• possession
• noun + noun compounds

Examples:

• باب البيت = the door of the house / the house door
• كاشف الدخان = smoke detector
• إنذار الحريق = fire alarm

In this structure:

1. the first noun is إنذار
2. the second noun is الحريق
3. the first noun does not take ال
4. the second noun is in the genitive role

That is one of the key rules of iḍāfa.

In an iḍāfa phrase:

• the first noun usually does not take الـ
• the second noun can be definite, and if it is definite, the whole phrase becomes definite

So:

• إنذار حريق could mean a fire alarm or alarm of a fire in a less specific sense
• إنذار الحريق means the fire alarm

Even though إنذار itself has no الـ, the whole phrase becomes definite because the second noun الحريق is definite.

The same thing happens in:

• بابُ البيتِ = the door of the house
• مديرُ المدرسةِ = the school principal

Yes, here قرب means near or close to.

In usage, قرب often functions like a preposition, followed by a noun in the genitive sense:

• قرب كاشف الدخان = near the smoke detector

You may also see:

• بالقرب من = near
• قريب من = close to

So these are all related:

• قرب كاشف الدخان
• بالقرب من كاشف الدخان
• قريب من كاشف الدخان

The version in your phrase is compact and very natural for signs and labels.

كاشف الدخان is another iḍāfa construction.

• كاشف = detector
• الدخان = the smoke

So:

• كاشف الدخان = smoke detector
• literally: detector of smoke

This is a very common way Arabic builds compound nouns.

Compare:

• جهازُ الحاسوب = computer device
• مفتاحُ السيارة = car key
• كاشفُ المعادن = metal detector

So both main noun groups in the sentence are iḍāfa phrases:

• إنذار الحريق
• كاشف الدخان

Usually حريق refers to a fire in the sense of a blaze, burning incident, or dangerous fire, not just fire as a natural element.

So:

• نار often means fire more generally
• حريق often means fire as an accident, blaze, or emergency

That is why إنذار الحريق is the normal expression for fire alarm.

Similarly:

• طفاية حريق = fire extinguisher
• خروج الطوارئ = emergency exit

So in this context, الحريق is exactly the right word.

Even if the meaning has already been given to the learner, a natural way to interpret it is:

• Fire alarm near the smoke detector
• or, in fuller English, The fire alarm is near the smoke detector

The exact wording depends on context.

If this appears on:

• a map
• a building plan
• a label
• a safety sign

then the short sign-style reading is best:

• Fire alarm near the smoke detector

If you are turning it into a full sentence, then:

• The fire alarm is near the smoke detector

They are related, but they are not used in exactly the same way.

• قرب here works like near
• قريب is an adjective meaning near/close

Examples:

• إنذار الحريق قرب كاشف الدخان = The fire alarm is near the smoke detector
• إنذار الحريق قريبٌ من كاشف الدخان = The fire alarm is close to the smoke detector

So:

• قرب + noun
• قريب من + noun

Both are correct, but the first is more compact and common in signage.

Not necessarily. This wording sounds especially natural in written, functional contexts such as:

• safety labels
• floor plans
• building instructions
• technical descriptions

In normal conversation, a speaker might prefer a fuller sentence, such as:

• إنذار الحريق قريب من كاشف الدخان
• يوجد إنذار الحريق قرب كاشف الدخان

So the phrase you have is correct, but it has a concise, practical style rather than a conversational one.

In everyday written Arabic, especially without full vowel markings, case endings are usually not written.

But if we fully analyze it, the phrase could be read something like:

• إنذارُ الحريقِ قربَ كاشفِ الدخانِ

Very roughly:

• إنذارُ as the main noun
• الحريقِ as the second term of iḍāfa
• قربَ as an adverbial/prepositional expression
• كاشفِ after قرب
• الدخانِ as the second term of another iḍāfa

For most learners, the most important thing is not memorizing every ending here, but recognizing the two iḍāfa phrases and the location word قرب.

A careful pronunciation would be approximately:

• in-dhāru l-ḥarīqi qurba kāshifi d-dukhān

A simpler learner-friendly approximation is:

• in-THAAR al-ha-REEQ qurb KAA-shif ad-du-KHAAN

A few notes:

• ذ in إنذار is like th in this
• ح in الحريق is a deeper h sound
• خ in الدخان is like the ch in Scottish loch or German Bach
• الـ in الدخان assimilates to the d sound, so you hear something like ad-dukhān, not al-dukhān

This kind of pronunciation detail is helpful, but for understanding the sentence, the grammar patterns matter even more.