يومض المصباح اليدوي.

A careful Modern Standard Arabic reading is:

yūmiḍu al-miṣbāḥu al-yadawiyyu

A simpler pronunciation without full case endings, which is closer to how many learners first say it, is:

yūmiḍ al-miṣbāḥ al-yadawī

A few notes:

• يومض = yūmiḍu
• المصباح = al-miṣbāḥu
• اليدوي = al-yadawiyyu
• ض is an emphatic d sound, often written ḍ
• ص is an emphatic s sound, written ṣ
• ā and ū show long vowels

Because Arabic very often allows, and often prefers, a verb-first sentence.

So:

• يومض المصباح اليدوي = verb + subject
• literally, something like Flashes the flashlight

This is a normal Arabic sentence type called a verbal sentence.

English usually prefers subject + verb:

• The flashlight flashes

Arabic can also say:

• المصباح اليدوي يومض

That version is also correct, but the given sentence is a very natural MSA verb-first structure.

يومض is a present/imperfect verb, third person, singular, masculine.

It means:

• it flashes
• it blinks
• it is flashing

Which English translation fits best depends on context.

So in this sentence, يومض matches the subject المصباح because مصباح is:

• singular
• masculine

Because Arabic verbs already include information about the subject.

In يومض, the verb itself already tells you:

• third person
• singular
• masculine

So Arabic does not need a separate pronoun like it here.

In other words, يومض already contains the idea of it flashes.

Then the noun المصباح اليدوي is added to state exactly what that it is.

The Arabic imperfect/present can cover several meanings that English separates.

So يومض can mean:

• flashes
• is flashing
• does flash

Context decides which English translation is best.

With no extra context, English might translate this as either:

• The flashlight flashes
• The flashlight is flashing

Both are reasonable.

Because Arabic often expresses this idea as a noun plus an adjective:

• مصباح = lamp / light
• يدوي = hand-held / manual

So:

• مصباح يدوي = a flashlight
• المصباح اليدوي = the flashlight

This is not an idafa construction. It is a regular noun + adjective combination.

So اليدوي is describing what kind of lamp it is: a hand-held one.

Because اليدوي is an adjective, and Arabic adjectives must agree with the noun they describe in definiteness.

Here:

• المصباح = the lamp
• اليدوي = the hand-held

Together they mean:

• the hand-held lamp
• naturally, the flashlight

If the noun were indefinite, the adjective would also be indefinite:

• مصباح يدوي = a flashlight

So this matching is very important in Arabic adjective phrases.

Arabic adjectives agree with the noun in:

• gender
• number
• definiteness
• case

Here, المصباح is:

• masculine
• singular
• definite

So اليدوي is also:

• masculine
• singular
• definite

That is why the phrase is:

• المصباح اليدوي

and not some other form.

In fully vocalized MSA, the sentence is:

يومِضُ المصباحُ اليدويُّ

The endings are -u because:

• يومِضُ is a present-tense verb in the indicative
• المصباحُ is the subject, so it is nominative
• اليدويُّ is an adjective describing the subject, so it also takes the nominative

In ordinary Arabic writing, these short vowels are usually omitted, which is why you normally see:

يومض المصباح اليدوي

Yes. It comes from the root:

• و م ض

which has to do with flashing or gleaming.

The verb here is from أومضَ in the past tense, and its present form is:

• يومِضُ

If you know that, it becomes easier to recognize related forms and dictionary entries.

For a learner, the key practical point is:

• أومضَ = flashed / blinked
• يومِضُ = flashes / is flashing

Yes, absolutely.

Both are grammatical:

• يومض المصباح اليدوي
• المصباح اليدوي يومض

The difference is mainly in sentence structure and emphasis:

• يومض المصباح اليدوي is a typical verbal sentence
• المصباح اليدوي يومض is a subject-first version

In simple contexts, both can be translated the same way in English.