الجيب في البنطال.

Word by word:

• الجيب = the pocket
• في = in
• البنطال = the trousers / the pants

So the whole sentence means something like The pocket is in the trousers or The pocket is in the pants.

In Arabic, present-tense sentences often do not use a separate word for is / are.

So:

• الجيب في البنطال literally looks like the pocket in the trousers
• but it naturally means The pocket is in the trousers

This is very normal in Arabic. The verb to be is usually omitted in the present tense.

In MSA, it can be understood as a complete nominal sentence.

Its structure is:

• الجيب = the topic / subject
• في البنطال = a prepositional phrase telling where it is

So yes, it can function as a full sentence meaning The pocket is in the trousers.

الـ is the Arabic definite article, meaning the.

So:

• جيب = a pocket or just pocket
• الجيب = the pocket
• بنطال = trousers / pants
• البنطال = the trousers / the pants

Arabic uses الـ separately on each noun that is definite. It does not work like English, where one the can sometimes cover a larger phrase.

في is the common preposition meaning in.

So:

• في البيت = in the house
• في السيارة = in the car
• في البنطال = in the trousers

It introduces the place or location.

A simple pronunciation is:

• al-jayb fi al-binTaal

A more careful MSA pronunciation with case endings would be:

• al-jaybu fī al-binTāli

A few notes:

• ج in standard learning materials is often pronounced like j in job
• ط is an emphatic t, heavier than normal ت
• long ā in بنطال is held a little longer

If you fully vocalize it, a common form is:

• الجَيْبُ في البِنْطالِ

Why?

• الجيبُ ends in -u because it is the subject/topic of the nominal sentence
• البنطالِ ends in -i because it comes after the preposition في

In normal Arabic writing, these short vowel endings are usually not written, so learners often see just:

• الجيب في البنطال

This is a very normal Arabic order for a simple nominal sentence:

• subject/topic
  • prepositional phrase

So:

• الجيب = the pocket
• في البنطال = in the trousers

Putting the location after the noun is natural and straightforward. Other word orders are possible in some contexts, but this one is the basic, neutral choice.

In Arabic, بنطال is typically treated as a singular noun even though English often uses the plural pants.

So Arabic says:

• بنطال = trousers / pants
• البنطال = the trousers / the pants

This is one of those places where Arabic and English organize clothing words differently.

جيب is masculine.

That matters when you use adjectives or pronouns with it. For example, if you later refer to the pocket, you would use masculine agreement.

Yes, but the meaning changes.

• الجيب في البنطال = the pocket is in the trousers
• جيب في بنطال = a pocket is in trousers / a pocket in trousers

Without الـ, the nouns become indefinite, which usually sounds less specific and may not fit the intended meaning.

So if the idea is a specific pocket and specific trousers, الجيب في البنطال is the natural form.

They are fully pronounced here as al- because both ج and ب are moon letters, not sun letters.

So you say:

• al-jayb
• al-binTaal

There is no merging of the l sound in these two words.