الحاشية واسعة، في حين أن الخصر ضيق.

In Arabic, a present-tense sentence like this usually does not use an explicit verb meaning is.

So:

الحاشية واسعة
literally looks like
the hem / edge wide

but it means:

The hem / edge is wide.

This is called a nominal sentence. If you wanted was or will be, Arabic would normally use a verb such as كان or سيكون.

Because the adjectives match the nouns they describe in gender.

• الحاشية is grammatically feminine
• الخصر is grammatically masculine

So the adjectives match:

• واسعة = feminine form of wide
• ضيّق = masculine form of narrow

A learner-friendly way to think of it is:

• واسع → masculine
• واسعة → feminine

and:

• ضيّق → masculine
• ضيّقة → feminine

Because here they are predicates, not attributive adjectives.

Compare these two patterns:

• الحاشية واسعة = The hem is wide
• الحاشية الواسعة = the wide hem

In the sentence you gave, واسعة and ضيّق are telling us something about the subject, so they are usually indefinite in form.

This is a very common pattern in Arabic:

• البيت كبير = The house is big
• not البيت الكبير if you mean a full sentence

Because البيت الكبير means the big house, not the house is big.

في حين أن is a connector meaning something like:

• while
• whereas
• while it is the case that

In this sentence, it introduces a contrast:

• الحاشية واسعة = one description
• في حين أن الخصر ضيق = a contrasting description

So the overall sense is:

The hem is wide, whereas the waist is narrow.

It is a fairly formal and written-style expression in Modern Standard Arabic.

Here, أن is understood as أنَّ and is pronounced anna.

That matters because Arabic has two similar-looking forms:

• أنْ = an, usually before a verb
• أنَّ = anna, usually before a noun clause

In your sentence, it is the second one: أنَّ.

So:

في حين أن الخصر ضيق

is understood as:

في حينِ أنَّ الخصرَ ضيّقٌ

Grammatically, أنَّ introduces a nominal clause and makes its noun accusative.

Because normal Arabic writing usually leaves out the short vowel endings.

So in ordinary spelling you see:

الخصر

But with full case endings, it would be:

الخصرَ

The difference is real grammatically, but it is often invisible in unvowelled text.

This happens all the time in Arabic. Readers are expected to recover the correct grammar from context.

A fully vocalized version would be:

الحاشيةُ واسعةٌ، في حينِ أنَّ الخصرَ ضيِّقٌ.

A rough transliteration is:

al-ḥāshiyatu wāsiʿatun, fī ḥīni anna al-khaṣra ḍayyiqun.

A few notes:

• الحاشيةُ is nominative because it is the subject of the first nominal sentence
• واسعةٌ is the predicate of that sentence
• أنَّ introduces the second clause
• الخصرَ is accusative after أنَّ
• ضيِّقٌ is the predicate of the second clause

In normal reading, especially outside careful grammatical recitation, those final short vowels are often not pronounced fully.

Because Arabic script usually omits:

• short vowels
• shadda marks

So the spelling ضيق can stand for the fully vocalized adjective ضيّق.

In this sentence, context makes the intended reading clear: after الخصر, you expect a predicate adjective meaning narrow.

So a learner should understand it here as:

ضيّق = narrow

It is a nominal sentence: in Arabic grammar, جملة اسمية.

Its two main parts are:

• الحاشية = the subject (مبتدأ)
• واسعة = the predicate (خبر)

The second part, after في حين أنَّ, is also a nominal clause:

• الخصر = the noun of أنَّ
• ضيّق = its predicate

So the sentence is basically two linked descriptive clauses.

Not necessarily. حاشية can mean different but related things depending on context, such as:

• margin
• edge
• border
• hem
• even annotation or gloss in other contexts

Because your sentence also mentions الخصر (the waist), the clothing-related meaning is the natural one here.

So a learner should remember that many Arabic nouns are context-sensitive, and the surrounding words help narrow down the exact meaning.

Yes. Arabic gives you several ways to link the two ideas.

For example:

• الحاشية واسعة، والخصر ضيّق.
  The hem is wide, and the waist is narrow.

• الحاشية واسعة، لكن الخصر ضيّق.
  The hem is wide, but the waist is narrow.

• الحاشية واسعة، بينما الخصر ضيّق.
  The hem is wide, while the waist is narrow.

Compared with these, في حين أن sounds a bit more formal and written.

Yes. This is a very normal word order for a nominal sentence:

• subject + predicate
• الحاشية واسعة
• الخصر ضيّق

Arabic can sometimes change the order for emphasis or style, but the order here is straightforward and standard for learners to recognize.