أين الحمام في هذا المبنى، في الطابق الثاني أم في الطابق الثالث؟

أين means where and is the standard MSA question word for asking about location.

So:

• أين الحمام؟ = Where is the bathroom?
• أين الحمام في هذا المبنى؟ = Where is the bathroom in this building?

In Arabic, أين often comes at the beginning of the sentence, just like where in English.

In the present tense, Arabic usually does not use a separate word for is / are in simple sentences like this.

So:

• الحمام في الطابق الثاني literally: the bathroom in the second floor
• natural English: The bathroom is on the second floor

This is very normal in Arabic. The verb to be is usually omitted in present-tense statements and questions.

Here, الحمام means the bathroom / restroom / toilet.

A learner may notice that حمام can also mean other things in Arabic, especially:

• bath
• pigeons/doves in some contexts

But in this sentence, because we are asking about a place inside a building and comparing floors, the meaning is clearly bathroom/restroom.

هذا means this, and المبنى means the building.

Together:

• هذا المبنى = this building

This works because مبنى is grammatically masculine, so it takes the masculine demonstrative هذا.

If the noun were feminine, Arabic would normally use هذه instead.

The final ى is called alif maqṣūrah. It looks like ي without dots and usually represents a final ā sound.

So المبنى is pronounced roughly al-mabnā, not al-mabni.

This is just part of the spelling of the word مبنى (building). It is something learners see in many Arabic words.

في means in / on here, depending on natural English translation.

Arabic often repeats the preposition in both parts of an either/or type question:

• في الطابق الثاني
• أم في الطابق الثالث

This makes the sentence clear and balanced. English can sometimes avoid repetition, but Arabic commonly keeps it.

So the structure is basically:

• on the second floor
• or on the third floor

This is a very common question.

In this sentence, أم is used because the speaker is offering two specific alternatives after a question:

• في الطابق الثاني أم في الطابق الثالث؟
• on the second floor or on the third floor?

A simple way to think about it:

• أم = or in a question with two explicit choices
• أو = general or

So here أم is the more natural MSA choice because the speaker is asking which of the two options is correct.

الطابق means the floor or the story of a building.

So:

• الطابق الثاني = the second floor
• الطابق الثالث = the third floor

This is standard MSA vocabulary for levels of a building.

These are ordinal numbers:

• الثاني = second
• الثالث = third

They act like adjectives and describe الطابق.

So:

• الطابق الثاني = literally the floor the-second
• natural English: the second floor

In Arabic, adjectives usually come after the noun they describe, unlike in English.

Because Arabic adjectives usually match the noun in definiteness.

Since the noun is definite:

• الطابق = the floor

the adjective must also be definite:

• الثاني = the second
• الثالث = the third

So Arabic says:

• الطابق الثاني
• not normally الطابق ثاني in correct MSA

This is an important agreement rule: adjectives match the noun in definiteness, gender, number, and case.

Because in Arabic, descriptive adjectives normally come after the noun.

So:

• الطابق الثاني = the second floor
• المبنى الكبير = the big building

This is the regular Arabic pattern: noun + adjective

English usually does the opposite: adjective + noun

Arabic uses في very naturally for location inside a place or within a level of a building.

So although English usually says:

• on the second floor

Arabic says:

• في الطابق الثاني

Word-for-word it looks like in the second floor, but the natural translation is on the second floor.

This is a normal difference between the two languages.

Yes. It is a perfectly natural MSA sentence.

Structure:

• أين الحمام في هذا المبنى = Where is the bathroom in this building
• في الطابق الثاني أم في الطابق الثالث؟ = on the second floor or on the third floor?

It asks for the location of the bathroom and gives two possible options.

Yes. Arabic often allows shorter versions if the context is clear.

For example:

• أين الحمام؟
• في الطابق الثاني أم الثالث؟

That shorter form may be understood in context, but the full sentence:

• أين الحمام في هذا المبنى، في الطابق الثاني أم في الطابق الثالث؟

is clearer and more formal.

A careful MSA-style pronunciation would be roughly:

ʾayna al-ḥammāmu fī hādhā al-mabnā, fī al-ṭābiqi al-thānī am fī al-ṭābiqi al-thālith?

A simpler learner-friendly approximation:

AY-na al-ham-MAAM fee HAA-thaa al-mab-NAA, fee at-TAA-biq ath-THAA-nee am fee at-TAA-biq ath-THAA-lith?

A few notes:

• أين = ayna
• ح in الحمام is a deeper h sound than English h
• ث in الثاني / الثالث sounds like th in think
• the ال before some letters changes in pronunciation, so الثاني sounds like ath-thānī, not al-thānī

In fully vocalized formal MSA, the sentence could be written:

أَيْنَ الحَمَّامُ فِي هٰذَا الْمَبْنَى، فِي الطَّابِقِ الثَّانِي أَمْ فِي الطَّابِقِ الثَّالِثِ؟

The important case endings here are:

• الحمّامُ with -u because it is the subject/topic of the question
• الطابقِ with -i because it comes after في
• الثاني / الثالث also take -i in full formal grammar because they describe الطابقِ

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

أين الحمام في هذا المبنى، في الطابق الثاني أم في الطابق الثالث؟

The comma is mainly a punctuation choice to make the sentence easier to read.

It separates:

• the main question
• the two alternatives

Arabic punctuation is useful, but you may see slightly different punctuation styles in different texts. The meaning of the sentence does not really depend on the comma here.