ثجج (root thjj)

The lexicographers in chronological order, from al-Khalīl to Lane.

No excerpt from al-Khalīl or al-Rāghib is available here, so the sequence begins with al-Jawharī as Lane reports him. Lane cites the Ṣiḥāḥ for the transitive thajjahu, 'he poured it out', and for thajj as the flowing of the blood of the sacrificial victim brought to the Meccan sanctuary. Ibn Fāris reduces the root to one aṣl, the pouring of a thing (ṣabb). His witnesses are Q 78:14, Abū Dhuʾayb's verse on rain-clouds whose water is thajīj, and two ḥadīths: 'the best pilgrimage is al-ʿajj wa-l-thajj', glossed as loud talbiya and the streaming blood of the hady, and the mustaḥāḍa's 'innī athujjuhu thajjan', where the word describes a heavy flow of blood. Lane, drawing on the later lexica, distinguishes intransitive thajja, yathijju 'it flowed, poured forth vehemently or copiously' from transitive thajja, yathujju 'he poured it'. He also records the synonyms inthajja and tathajthaja. Across these sources the sense stays fixed on heavy outpouring, and it is applied equally to water and to blood.

What the theorists of sound symbolism would say of these letters. Speculative by nature.

In Ibn ʿArabī's scheme of the letters in the Breath of the Merciful, thāʾ corresponds to plants and jīm to the starless Atlas sphere, the sphere of the zodiac. Read symbolically, the pair would join a heavenly origin to vegetation, which fits rain poured from the clouds to bring forth grain and plants, as in Q 78:14–15. In al-Dabbāgh's account, thāʾ indicates light or darkness, and jīm, when nothing in its context marks prophecy or sainthood, indicates a good that never ceases. A theorist in Ibn Jinnī's line might also take the doubled final consonant, and the reduplicated tathajthaja, as imitating repeated or continuous flow. Mainstream linguistics treats all such readings as suggestive at most.

The two-letter nucleus (Ibn Fāris's own chapters) and the permutations of the letters (Ibn Jinnī).

Two siblings share the nucleus th-j in Ibn Fāris's chapter. Th-j-r denotes the wide, broad part of a thing, as in thujrat al-wādī, the broad middle of a valley. Th-j-m he does not count as a true aṣl, recording only its use for rain that continues for days. Set beside thajj, the siblings offer a loose field of copious water (thajj, thajm) and the broad valley floor that receives it (thujra); this is a juxtaposition and not an established derivation. Neither permutation, j-th-j or j-j-th, is attested, so Ibn Jinnī's greater derivation (ishtiqāq akbar) has no material to work on here.

Cognates in the sister languages, and whether the word was borrowed.

I know of no confident cognate in Hebrew, Aramaic or Syriac, Akkadian, Geʿez, or Epigraphic South Arabian. The root appears to be an inner-Arabic formation, possibly expressive in origin. Jeffery does not list thajjāj among the foreign words of the Qurʾān, and nothing suggests borrowing.

How the classical exegetes read the word in the Quran.

The only occurrence is Q 78:14, 'and We sent down from the muʿṣirāt water pouring abundantly' (māʾan thajjājan). The classical exegetes gloss thajjāj as water poured out copiously and in continuous succession. Al-Ṭabarī reports early authorities to this effect. Most commentators take the form faʿʿāl as intensive, conveying heavy, sustained outpouring. They debate the muʿṣirāt themselves, rain-laden clouds or winds that press out the rain, more than they debate thajjāj, whose meaning they treat as settled. Al-Rāzī places the verse within the sūra's argument from the ordered gifts of creation to resurrection.