The sound masculine plural adds ـون -ūn or ـين -īn without rebuilding the singular stem: معلّم muʿallim → معلّمون muʿallimūn “male teachers.” It is “sound” because the stem remains recognizable, and “masculine” because its central use is male human—or mixed human—reference.
It is not the automatic plural of every masculine noun. رجل rajul “man” becomes رجال rijāl, and طفل ṭifl “child” commonly becomes أطفال ʾaṭfāl. Choosing this plural is partly lexical; once it is chosen, its case alternation and construct form are regular.
Who normally takes this plural?
The most productive class contains masculine human nouns and descriptors, especially professions, participles, and relational adjectives.
| Singular | Plural at pause | Meaning |
|---|---|---|
| مُعَلِّم muʿallim | مُعَلِّمُون muʿallimūn | male teachers |
| مُهَنْدِس muhandis | مُهَنْدِسُون muhandisūn | male engineers |
| بَاحِث bāḥith | بَاحِثُون bāḥithūn | male researchers |
| مُجْتَهِد mujtahid | مُجْتَهِدُون mujtahidūn | diligent men or boys |
| مِصْرِيّ miṣriyy | مِصْرِيُّون miṣriyyūn | Egyptian men or a mixed Egyptian group |
معلم، معلمون؛ مهندس، مهندسون.
muʿallim, muʿallimūn; muhandis, muhandisūn.
A male teacher, male teachers; a male engineer, male engineers.
A mixed-gender human group normally uses the masculine plural. An all-female group uses feminine forms such as معلّمات. But lexical convention still matters: common kinship terms and basic human nouns frequently have broken plurals.
رجل، رجال؛ طفل، أطفال.
rajul, rijāl; ṭifl, ʾaṭfāl.
A man, men; a child, children.
There is no honest rule that predicts every choice. A dictionary entry should be learned as singular + plural, not as a bare singular awaiting a suffix.
Case: ـون for nominative, ـين for accusative and genitive
The full connected endings are nominative ـونَ -ūna and accusative/genitive ـينَ -īna. At pause, final short a disappears, giving -ūn and -īn. The written long-vowel contrast remains visible even in unvocalized text.
| Case | Indefinite | Definite | Core use |
|---|---|---|---|
| nominative | مُعَلِّمُونَ | الْمُعَلِّمُونَ | often subject or predicate |
| accusative | مُعَلِّمِينَ | الْمُعَلِّمِينَ | often direct object |
| genitive | مُعَلِّمِينَ | الْمُعَلِّمِينَ | after a preposition or as an iḍāfa dependent |
The final n belongs to the plural suffix; it is not tanwīn. That is why the definite المعلمون retains n, and why an indefinite sound masculine plural does not receive an additional tanwīn mark.
وصل معلمون جدد.
waṣala muʿallimūna judud.
New male teachers arrived. (Nominative -ūna connected.)
كرمت المدرسة معلمين متميزين.
karramati l-madrasatu muʿallimīna mutamayyizīn.
The school honored outstanding male teachers.
تحدثت مع معلمين جدد.
taḥaddathtu maʿa muʿallimīna judud.
I spoke with new male teachers.
The last two forms look alike because accusative and genitive share ـين. Syntax—not the suffix alone—tells you which case is present.
Construct state: remove nūn
When a sound masculine plural is the first member of an iḍāfa, it loses final ن n. Nominative ـون becomes ـو -ū, while accusative/genitive ـين becomes ـي -ī. The following noun makes the whole phrase definite or indefinite.
| Case of construct head | Free form | Construct form |
|---|---|---|
| nominative | مُعَلِّمُونَ | مُعَلِّمُو الْمَدْرَسَةِ |
| accusative | مُعَلِّمِينَ | مُعَلِّمِي الْمَدْرَسَةِ |
| genitive | مُعَلِّمِينَ | مُعَلِّمِي الْمَدْرَسَةِ |
معلمو المدرسة مستعدون.
muʿallimū l-madrasati mustaʿiddūn.
The school's male teachers are ready.
قابلت معلمي المدرسة.
qābaltu muʿallimī l-madrasa.
I met the school's male teachers.
استمعت إلى معلمي المدرسة.
ʾistamaʿtu ʾilā muʿallimī l-madrasa.
I listened to the school's male teachers.
Do not put الـ on the construct head: معلمو المدرسة, not المعلمو المدرسة. The dependent المدرسة supplies definiteness to the phrase.
Human agreement and word order
A sound masculine plural with human reference takes masculine plural adjectives, predicates, pronouns, and—when subject first—verbs.
المهندسون الجدد مستعدون.
al-muhandisūna l-jududu mustaʿiddūn.
The new male engineers are ready.
The adjective الجدد is itself a broken plural. Agreement can be plural masculine even when the agreeing word does not carry ـون. Syntactic agreement and plural shape are separate facts.
Verb order adds another distinction:
وصل المهندسون.
waṣala l-muhandisūn.
The male engineers arrived. (Verb first: singular masculine verb.)
المهندسون وصلوا.
al-muhandisūna waṣalū.
The male engineers arrived. (Subject first: plural verb.)
The postverbal explicit subject in the first sentence is plural, but neutral formal MSA uses a singular verb before it. The subject-first sentence shows full plural agreement.
A plural-looking ending does not guarantee human agreement
A small set of nouns are treated morphologically like the sound masculine plural without denoting male humans. سنون sinūn “years,” for example, has the ending but takes normal nonhuman plural agreement: feminine singular.
كانت السنون الماضية صعبة.
kānati s-sinūnu l-māḍiyatu ṣaʿba.
The past years were difficult.
The adjective الماضية and predicate صعبة are feminine singular. This proves why suffix shape cannot determine the rest of the sentence. Human/rational meaning licenses plural agreement; ordinary nonhuman/non-rational reference triggers feminine singular agreement. For the neighboring suffix system, see Sound Feminine Plural ـات.
Contemporary informational use
شارك باحثون ومهندسون في المؤتمر.
shāraka bāḥithūna wa-muhandisūna fī l-muʾtamar.
Researchers and engineers participated in the conference.
Both coordinated nouns are human sound masculine plurals. Because the verb precedes the explicit plural subject, شارك remains singular masculine.
Common Mistakes
Adding ـون to every masculine human noun
❌ رجلون
Incorrect — رجل has the lexical broken plural رجال.
✅ رجال.
rijāl.
Men.
Using nominative ـون for an object
❌ قابلت المعلمون
Incorrect — the direct object needs accusative ـين.
✅ قابلت المعلمين.
qābaltu l-muʿallimīn.
I met the male teachers.
Keeping nūn on an iḍāfa head
❌ معلمون المدرسة
Incorrect — the construct head loses ن and cannot take the article.
✅ معلمو المدرسة.
muʿallimū l-madrasa.
The school's male teachers.
Using “two + plural” instead of the dual
❌ اثنان معلمون
Incorrect for neutral ‘two teachers’ — use the dual noun.
✅ معلمان.
muʿallimān.
Two male teachers.
Giving a nonhuman ـون noun masculine plural agreement
❌ السنون طويلون
Incorrect — nonhuman plural سنون takes feminine singular agreement.
✅ السنون طويلة.
as-sinūnu ṭawīla.
The years are long.
Key Takeaways
- Sound masculine ـون/ـين is productive mainly with male or mixed human roles and descriptors, not every masculine noun.
- Use nominative ـونَ -ūna and accusative/genitive ـينَ -īna; neither ending is tanwīn.
- Drop final nūn when the plural is an iḍāfa head: معلمو / معلمي.
- Agreement follows human versus nonhuman meaning and verb position, not suffix shape alone.
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