The word dibna is fairly well-attested in the Mandaic corpus, and almost completely unattested elsewhere. The Drower and Macuch entry for it (p. 106) reads,
dibna (Ar. loan-w. دبن Jb ii 45 n. 1) sheepfold. kḏ raia ṭaba laqnẖ ḏ-ldibnaihun dabarlun Gy 177:21 like a good shepherd that guideth his sheep to their fold; aqna ldiblaihun Gs 10:23 ; dibna ṭaba Jb 40:12; ladiba šauar dibnan Jb 41:5 no wolf leapeth into our sheepfold; laiil ganaba ldibnaiin Jb 41:7 a thief doth not enter their fold; alit ldibna Jb 42:5 I entered the sheepfold; baba ḏ-dibna Jb 42:11; tata ḏ-pašra unapqa mn dibnẖ JRAS 1937 592:27 a sheep which is loosed and comes forth from its fold.
At no point does it make clear whether the word was borrowed from Arabic or by Arabic. In his translation, Lidzbarski (1915, p. 45, fn. 1) suggests that the word has entered Arabic, and points to the Lisān al-ʿArab vol. XVII, p. 2 for confirmation, where it is described as a kind of “enclosure of canes made for sheep.” The Lisān‘s compiler, Ibn Manẓūr, identifies it as being of Persian origin.
In terms of the Orientalist literature, neither Wehr nor Lane mention the word. Charles Wilkins’ 1806 edition of John Richardson’s Dictionary, Persian, Arabic, and English includes this word (vol. 1, p. 425), as does Steingass’ 1884 Student’s Arabic-English Dictionary (p. 353), but Steingass neglects to include it in his Persian dictionary. The word seems to be utterly unattested outside of Mandaic and Arabic, save for Jacques Eugène Manna’s 1900 Vocabulaire chaldéen-arabe, which identifies deḇnā as “a dialect word of certain Aramaeans” for a sheep-pen. There, the trail runs cold until we come to Lidzbarski’s translation and the Drower and Macuch dictionary.