The preposition بـ (bi-) presents something as closely involved in an event: an instrument used to do it, a means by which it happens, a manner accompanying it, or something brought into contact with another thing. That compact relation extends to price, cause, oaths, and many fixed verb and adjective complements. English translations therefore range across with, by, in, at, because of, and sometimes no preposition at all.
Unlike في or على, بـ is a one-letter clitic. It attaches to the following noun, article, or pronoun with no space: بقلم، بالقلم، به. It governs the genitive. The written forms ب القلم and ب هو are impossible divisions in standard Arabic, even though English writes its prepositions separately.
For the suffix inventory shared across the system, see Pronoun Suffixes after Prepositions. The uses and vowel behavior of بـ itself are developed here from first principles.
Instrument and physical contact
The clearest use of بـ marks the instrument brought into the action. The instrument is not merely present; it is the means by which the agent performs the event.
وقعت العقد بقلم أزرق.
waqqaʿtu l-ʿaqda biqalamin ʾazraq.
I signed the contract with a blue pen.
فتح الفني الصندوق بمفتاح خاص.
fataḥa l-fanniyyu ṣ-ṣundūqa bimiftāḥin khāṣṣ.
The technician opened the box with a special key.
The same close-association meaning covers grasping and contact. In أمسك بيد الطفل, the hand is what is held; بـ is selected by أمسك in this sense. With some verbs, omitting the preposition changes the construction or sounds less idiomatic.
أمسكت الأم بيد طفلها عند عبور الشارع.
ʾamsakati l-ʾummu biyadi ṭiflihā ʿinda ʿubūri sh-shāriʿ.
The mother held her child's hand while crossing the street.
اصطدمت الدراجة بالحاجز المعدني قرب المدخل.
iṣṭadamati d-darrājatu bil-ḥājizi l-maʿdiniyyi qurba l-madkhal.
The bicycle collided with the metal barrier near the entrance.
Here بالحاجز is spatial in the sense of contact, not location inside a space. Compare الدراجة في المرآب “the bicycle is in the garage,” where في locates it.
Means, transport, and communication
An instrument is usually a concrete object; a means can be a vehicle, technology, procedure, or channel. Arabic uses بـ for both, so the boundary between “with” and “by” is not grammatical.
سافرنا بالقطار لأن الطريق الجبلي كان مغلقا.
sāfarnā bil-qiṭāri li-ʾanna ṭ-ṭarīqa l-jabaliyya kāna mughlaqan.
We traveled by train because the mountain road was closed.
أرسلت الشركة الفاتورة بالبريد الإلكتروني.
ʾarsalati sh-sharikatu l-fātūrata bil-barīdi l-ʾilikturūniyy.
The company sent the invoice by email.
يمكن دفع الرسوم ببطاقة مصرفية أو بتحويل بنكي.
yumkinu dafʿu r-rusūmi bibiṭāqatin maṣrifiyyatin ʾaw bitaḥwīlin bankiyy.
The fees can be paid by bank card or bank transfer. (Formal.)
English by also introduces the agent of a passive: “the report was written by the committee.” Contemporary formal Arabic commonly uses من قبل اللجنة for an explicitly expressed institutional agent, not an automatic بـ. Do not turn “by = بـ” into a universal equation.
Manner, state, and rates
Many manner expressions are بـ + noun: بهدوء “calmly,” بسرعة “quickly,” بعناية “carefully,” بوضوح “clearly.” Arabic often packages an English adverb as a prepositional phrase.
شرحت الطبيبة الخطة بوضوح، وأجابت عن كل الأسئلة.
sharaḥati ṭ-ṭabībatu l-khuṭṭata biwuḍūḥin, wa-ʾajābat ʿan kulli l-ʾasʾila.
The doctor explained the plan clearly and answered every question.
تعامل الموظف مع الشكوى باهتمام واحترام.
taʿāmala l-muwaẓẓafu maʿa sh-shakwā bihtimāmin wa-ḥtirām.
The employee handled the complaint with care and respect.
Rates and measurement can also use بـ: بسرعة مئة كيلومتر في الساعة “at a speed of one hundred kilometers per hour” and بنسبة خمسة بالمئة “by/at a rate of five percent.” This is an abstract scale use, not a general marker for every English at.
ارتفعت المبيعات بنسبة خمسة بالمئة خلال الربع الأخير.
irtafaʿati l-mabīʿātu binisbati khamsatin bil-miʾati khilāla r-rubʿi l-ʾakhīr.
Sales rose by five percent during the final quarter. (Formal.)
Price and exchange
With buying, selling, renting, and valuation, بـ introduces the price or rate of exchange. The price is construed as the means or consideration by which the transaction occurs.
اشتريت القاموس بثلاثين دولارا من متجر الجامعة.
ishtaraytu l-qāmūsa bithalāthīna dūlāran min matjari l-jāmiʿa.
I bought the dictionary for thirty dollars at the university store.
بكم تؤجرون هذه القاعة لمدة ساعتين؟
bikam tuʾajjirūna hādhihi l-qāʿata limuddati sāʿatayn?
How much do you charge to rent out this hall for two hours?
بكم؟ is literally “for how much?” The interrogative كم follows the clitic directly. An English for in this price sense therefore does not call for لـ.
Cause, emotion, and predicate government
Arabic frequently uses بـ after verbs and adjectives of emotion, belief, interest, beginning, and sensation. Learn the whole frame: فرح بـ “was delighted by,” شعر بـ “felt,” آمن بـ “believed in,” اهتم بـ “was interested in/cared about,” بدأ بـ “began with,” and تميز بـ “was characterized by.”
فرح الأطفال بالخبر، لكنهم انتظروا تأكيده.
fariḥa l-ʾaṭfālu bil-khabari, lakinnahum intaẓarū taʾkīdah.
The children were delighted by the news, but they waited for confirmation.
تهتم الباحثة بتأثير الجفاف في الزراعة المحلية.
tahtammu l-bāḥithatu bitaʾthīri l-jafāfi fī z-zirāʿati l-maḥalliyya.
The researcher is interested in the effect of drought on local agriculture. (Academic.)
يشعر بعض السكان بالقلق من ارتفاع الإيجارات.
yashʿuru baʿḍu s-sukkāni bil-qalaqi mini rtifāʿi l-ʾījārāt.
Some residents are concerned about rising rents.
The government contrast is lexical: شعر بالبرد “felt cold,” but أحس البرد can take a direct object; اهتم بالمشروع “took an interest in the project,” but ناقش المشروع “discussed the project” has no preposition. English does not predict the pattern.
Formal Arabic may also add an emphatic بـ to the predicate of ليس. Compare ordinary ليس التغيير ضروريا “the change is not necessary” with ليس التغيير بضروري “the change is by no means necessary.” Without بـ, the predicate of ليس is accusative; with this so-called additional bāʾ, it is genitive in form. This construction strengthens or styles the negation—it is not an instrumental use.
ليس هذا التغيير بضروري في المرحلة الحالية.
laysa hādhā t-taghyīru biḍarūriyyin fī l-marḥalati l-ḥāliyya.
This change is by no means necessary at the current stage. (Formal.)
Oaths and formal collocations
The bāʾ can introduce the entity by which an oath is sworn. بالله “by God” is a solemn or religious formula, not a neutral conversational filler to insert casually into every register. It still governs the genitive: fully vocalized بِاللَّهِ.
بالله لأقولن الحق ولو كان صعبا.
billāhi la-ʾaqūlanna l-ḥaqqa wa-law kāna ṣaʿban.
By God, I will certainly tell the truth even if it is difficult. (Solemn/religious.)
Formal prose contains many lexicalized bāʾ phrases: بموجب “pursuant to,” بالنيابة عن “on behalf of,” بالنسبة إلى “with regard to,” and بفضل “thanks to.” Their translations do not preserve a single English preposition.
وقع نائب الرئيس الاتفاق بالنيابة عن المؤسسة.
waqqaʿa nāʾibu r-raʾīsi l-ittifāqa bin-niyābati ʿani l-muʾassasa.
The vice president signed the agreement on behalf of the organization. (Formal.)
يحظر التصوير داخل المبنى بموجب اللوائح الجديدة.
yuḥẓaru t-taṣwīru dākhila l-mabnā bimūjabi l-lawāʾiḥi l-jadīda.
Photography inside the building is prohibited under the new regulations. (Formal.)
Attached pronouns: به, بها, and بي
Pronoun suffixes attach directly to بـ. Third-person بِهِ is bihi in connected speech; feminine بِهَا is bihā. First-person بِي is bī, with a long vowel but no doubled y.
| Complement | Fully vocalized form | Reading |
|---|---|---|
| me | بِي | bī |
| you (m.sg.) | بِكَ | bika |
| you (f.sg.) | بِكِ | biki |
| him/it | بِهِ | bihi |
| her/it | بِهَا | bihā |
| us | بِنَا | binā |
| them (m.) | بِهِمْ | bihim |
هذا هو النظام الذي تعمل به جميع الفروع.
hādhā huwa n-niẓāmu lladhī taʿmalu bihi jamīʿu l-furūʿ.
This is the system by which all the branches operate.
اتصل بي المدير وطلب تحديث الأرقام قبل الظهر.
ittaṣala bī l-mudīru wa-ṭalaba taḥdītha l-ʾarqāmi qabla ẓ-ẓuhr.
The director called me and asked for the figures to be updated before noon.
Common Mistakes
Copying the English preposition
❌ يهتم أخي في تاريخ الملاحة القديمة.
Incorrect in standard MSA—اهتم governs بـ, although English says ‘is interested in.’
✅ يهتم أخي بتاريخ الملاحة القديمة.
yahtammu ʾakhī bitārīkhi l-milāḥati l-qadīma.
My brother is interested in the history of ancient navigation.
Writing the one-letter preposition separately
❌ أرسلت الملف ب البريد الإلكتروني.
Incorrect—بـ is a clitic and must attach to البريد.
✅ أرسلت الملف بالبريد الإلكتروني قبل الظهر.
ʾarsaltu l-malaffa bil-barīdi l-ʾilikturūniyyi qabla ẓ-ẓuhr.
I sent the file by email before noon.
Giving the governed noun nominative case
❌ كتبت بالقلم، مع نطق القلم بالضمة.
Incorrect in fully inflected Arabic—بـ governs genitive القلمِ.
✅ كتبت بالقلم الأسود لأن الأزرق جف.
katabtu bil-qalami l-ʾaswadi li-ʾanna l-ʾazraqa jaff.
I wrote with the black pen because the blue one had dried out.
Stranding بـ
❌ هذه هي الأداة التي فتحت الصندوق ب.
Incorrect—formal Arabic attaches بـ to a resumptive pronoun.
✅ هذه هي الأداة التي فتحت بها الصندوق.
hādhihi hiya l-ʾadātu llatī fataḥtu bihā ṣ-ṣundūq.
This is the tool with which I opened the box.
Choosing a “to” construction from English alone
❌ أشرت للخطأ في الصفحة الأولى.
Incorrect in the intended meaning—أشار ‘pointed/referred to’ conventionally selects إلى.
✅ أشرت إلى الخطأ في الصفحة الأولى وشرحته.
ʾashartu ʾilā l-khaṭaʾi fī ṣ-ṣafḥati l-ʾūlā wa-sharaḥtuh.
I pointed to the error on the first page and explained it.
Key Takeaways
- بـ links an event closely to an instrument, means, manner, contact point, price, cause, or conventional complement.
- It is a one-letter clitic: write بالقطار، بقلم، به, never with a space after ب.
- It governs the genitive, while suffixed forms are به، بها، بي (bihi, bihā, bī).
- Learn whole frames such as اهتم بـ، شعر بـ، تميز بـ، بالنيابة عن; English with, by, in, and at do not define Arabic government.
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- على — on, over, and uponA1 — Use على for support, position above, obligation, directed attitudes, and the complements selected by common verbs and formal expressions.
- لـ — for, to, and belonging toA1 — Use لـ for recipients, beneficiaries, possession, purpose, allocation, and selected complements while mastering its article contraction and suffix vowels.
- في — in, at, and withinA1 — Use في for containment, settings, time frames, abstract domains, governed complements, and attached pronouns.
- Pronoun Suffixes after PrepositionsA2 — Attach pronoun complements to Arabic prepositions while choosing the base changes required by bi-, li-, maʿa, ʿinda, min, and ilā.