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ʿArūḍ or Arud (Arabic: العروض al-ʿarūḍ) is often called the Science of Poetry (Arabic: علم الشعر ʿilm aš-šiʿr). Its laws were laid down by Al-Khalil ibn Ahmad al-Farahidi (d. 786), an early Arab lexicographer and philologist, who did so after noticing that poems consisted of repeated syllables in each verse. He wrote his first book, Al-Ard, describing 15 types of verses. It is said that he used to climb down into a well in order to enjoy the poems during his study. Later Al-Akhfash al-Akbar described a 16th meter, al-Mutadārik.
Al-Khalil was primarily a grammarian, and he applied the grammatical terminology of his day based his used the terms ḥarf mutaḥarrik "mobile letter" and ḥarf sākin "quiescent letter" to devise a classification of syllables. A ḥarf mutaḥarrik is a consonant which is followed by a vowel, and a ḥarf sākin is a consonant which is not followed by a vowel. He combined these as fundamental prosodic elements to define a number of prosodic sequences.
ʿArūḍ is the study of poetic meters, which identifies the meter of a poem and determines whether the meter is sound or broken in lines of the poem. The study of ʿarūḍ began within the first century AH in a region called ʿArūḍ near Mecca in Saudi Arabia, which is why it was called ʿArūḍ.
The ʿArūḍ spelling is based on the ḥaraka (حركة) (which indicates that the letter above which it is placed is followed by a short vowel, either a (fatḥah َ ), u (ḍammah ُ ) or i (kasrah ِ ) .) and on the sukūn, also called sākin (سكون / ساكن) (which indicates that the letter above which it is placed is NOT followed by any short vowel - but by a long one it could). The fatḥa, ḍamma and kasra vowels are represented by the mutaḥarrik (which is a short horizontal line), and the sukūn or sākin by the usual sukūn character (which is shaped like a circle). There are mnemonic phrases that facilitate memorizing the ʿArūḍ patterns. One example of these mnemonic phrases is: (لم أر على ظهر جبل سمكة) (Literally meaning: I did not see a fish on top of a mountain)
For the purpose of identifying and writing out the ʿArūḍ, words are spelled out phonetically. For example, the word "al-karīm" ("the generous") is usually spelled "الكريم". In ʿArūḍ writing, it is written phonetically as "لكريم". The first letter after al- (definite particle) is a so-called moon letter (harf qamari), meaning the word is pronounced lkareem, so it is written this way for the purpose of the ʿArūḍ. Had the word started with a sun letter (harf shamsi), as in the word "al-shams" (meaning "the sun"), the word would be read aš-šams. This one, in ʿArūḍ writing, would be ششمس, while usually it would be written الشّمس. In ʿArūḍ writing, the šaddah, which symbolizes a doubling of a letter, is not written, and the letter on which it is put is written twice.
The Tafāʿīl are the meter units in the Arabic poetry system. In most sonnets there will be eight of those: four in the first verse and four in the second; in other cases, there will be six of them, meaning three in the first verse and three in the second. There is also a case in which their number is less than three: when the verses are only taken from complete poems to make a citation.
Al-Khalīl ibn Ahmad Al-Farahidi (718 - 786 A.D.) identified fifteen meters, and his student Al-Akhfash (الأخفش) identified an additional one.
A line of poetry, known as a bayt, is composed of two verse-halves, one of which is called the sadr (صدر) (literally Chest) and the other which is called the 'Ajuz (عجز) (literally belly). They are called by these terms because they represent the first part and the second part of a bayt.
The ṣadr and the 'ajuz has two parts each: - The sadr's last word is called the ʿArūḍ, and the rest of it is called ḥashū ṣ-ṣadr (حشو الصّدر) (meaning "the filling of the chest") - The 'ajuz's last word is called the ḍarb (literally "the hit"), and the rest of it is called ḥashū 'ajuz (حشو العجز) (meaning "the filling of the belly").
A particularity of the ḍarb is that its last consonant and the vowel that comes after it (the two last letters) are called the rawiyy (رويّ) and that its last two sākins, all the mutaḥarrik that are in between, and the last mutaḥarrik before them, is called the qāfīyah (قافية) or 'rhyme'.
The Buhūr, identified in a traditional method 
- 1 - Hazaj (هزج)
Tafā'īl: Mafāʿīlun Mafāʿīlun (مَفاعيلُن مَفاعيلُن)
- 2 - Wāfir (وافر) Tafā'īl: Mufāʿalatun Mufāʿalatun Faʿūlun (مُفاعَلَتُن مُفاعَلَتُن فَعولُن)
- 3 - Muḍāri' (مضارع) Tafā'īl: Mafāʿīlu Fāʿilātun (مَفاعيلُ فاعِلاتُن)
- 4 - Ṭawīl (طويل) Tafā'īl: Faʿūlun Mafāʿīlun Faʿūlun Mafāʿilun (فَعولُن مَفاعيلُن فَعولُن مَفاعِلُن)
- 5 - Mutaqārib (متقارب) Tafā'īl: Faʿūlun Faʿūlun Faʿūlun Faʿūlun (فَعولُن فَعولُن
- 6 - Ramal (رمل) Tafā'īl: Fāʿilātun Fāʿilātun Fāʿilun (فاعِلاتُن فاعِلاتُن فاعِلُن)
- 7 - Khafīf (خفيف) Tafā'īl: Fāʿilātun Mustafʿilun Fāʿilātun (فاعِلاتُن مُسْتَفْعِلُن فاعِلاتُن)
- 8 - Mujtathth (مجتثّ) Tafā'īl: Mustafʿilun Fāʿilātun (مُسْتَفْعِلُن فاعِلاتُن)
- 9 - Madīd (مديد) Tafā'īl: Fāʿilātun Fāʿilun Fāʿilātun (فاعِلاتُن فاعِلُن فاعِلاتُن)
- 10 - Rajaz (رجز) Tafā'īl: Mustafʿilun Mustafʿilun Mustafʿilun (مُسْتَفْعِلُن مُسْتَفْعِلُن مُسْتَفْعِلُن)
- 11 - Sarī' (سريع) Tafā'īl: Mustafʿilun Mustafʿilun Fāʿilun (مُسْتَفْعِلُن مُسْتَفْعِلُن فاعِلُن)
- 12 - Kāmil (كامل) Tafā'īl: Mutafāʿilun Mutafāʿilun Mutafāʿilun (مُتَفاعِلُن مُتَفاعِلُن مُتَفاعِلُن)
- 13 - Munsariħ (منسرح) Tafā'īl: Mustafʿilun Fāʿilat Muftaʿilun (مُسْتَفْعِلُن فاعِلاتْ مُفْتَعِلُن)
- 14 - Muqtaḑabb (مقتضب) Tafā'īl: Fāʿilatu Muftaʿilun (فاعِلاتُ مُفْتَعِلُن)
- 15 - Basīṭ (بسيط) Tafā'īl: Mustafʿilun Fāʿilun Mustafʿilun Fā'ilun (مُسْتَفْعِلُن فاعِلُن مُسْتَفْعِلُن فَعِلُن)
- 16 - Mutadārik (متدارك) Tafā'īl: Faʿilun Faʿilun Faʿilun Faʿilun (فَعِلُن فَعِلُن فَعِلُن فَعِلُن)
- AlNagdawi, Mohammad and others."Finding Arabic Poem Meter using Context Free Grammar", Journal of Communications and Computer Engineering, 2013.