رسب1 رَسَبَ, (S, M, A, &c.,) aor. ـُ (M, A, &c.,) inf. n. رُسُوبٌ (S, M, A, Mgh, Msb, K) and رَسْبٌ; (Msb;) and رَسُبَ, aor. ـُ (M, A, K;) It (a thing, S, Msb) sank, or subsided, (S, M, A, Mgh, Msb, K,) in water [&c.]. (S, M, A, Mgh, K.) b2:  [Hence,] رَسَبَتْ عَيْنَاهُ (tropical:)  His eyes sank [in their sockets]. (S, A.) b3:  And السَّيْفُ يَرْسُبُ فِى الضَّريبَةِ (tropical:)  The sword sinks, or disappears, in the thing struck with it. (TA.) 2 رسّب It precipitated a substance, or caused it to sink in a liquid: used in this sense in chymical works; but probably post-classical. See what next follows.]4 ارسب It caused [a thing] to sink: hence, in a trad., describing the people of Hell, إِذَا طَفَتْ بِهِمُ النَّارُ أَرْسَبَتْهُمُ الأَغْلَالُ When the fire shall raise them, and make them. to appear [or rather to swim upon its surface], the collars, by reason of their weight, shall make them to sink to the bottom thereof. (TA.) A2:  And ارسبوا Their eyes sank in their heads by reason of hunger. (K, TA.) 5 ترسّب It (a substance) became precipitated, or was caused to sink, in a liquid: used in this sense in chymical works; but probably postclassical.]رَسَبٌ and رُسَبٌ: see the next paragraph.رَسُوبٌ [What is wont to sink, or subside, in water &c. b2:  And hence,] Dregs amid water and blood: in this sense improperly pronounced رُسُوبٌ. (KL. [Golius, as on the same authority, explains it as meaning sedimentum aquæ, urinæ, etc.: hypostasis. See also the next paragraph.]) b3: [Hence also,] (tropical:)  A sword (S, M, A, K) that penetrates into, (S,) or that disappears in, (M, A, K,) the thing struck with it; (S, M, A, K;) and so ↓ رَسَبٌ (M, K) and ↓ رُسَبٌ (K, TA) and ↓ مِرْسَبٌ. (A, K, TA. [In the CK, by the omission of وَ after the last, this and the last but one are made to be appellations of a sword of Mohammad or of Soloman, and of a sword of El-Hárith Ibn-AbeeShemir.]) b4:  And (assumed tropical:)  The glans of the penis: (M, K:) app. because of its disappearance on the occasion of the act of جِمَاعِ. (M.) b5:  and (assumed tropical:)  Forbearing, or element; as also ↓ رَاسِبٌ. (K.) رُسَابَةُ المَآءش (JK and Mgh and K in art. تقن [in CK erroneously رَسَابَة]) [The sediment of water;] the thick matter that is borne by water [and that sinks to the bottom]. (Lth, Mgh in that art.) رَسُوبِىٌّ and ↓ مُتَرَسِّبٌ, terms used by Ibn-Seenà, are explained by Golius as meaning Having, or depositing, a sediment: but the former rather means having the nature of dregs, or sediment: and the latter, becoming, or that becomes, precipitated.]رَاسِبٌ (tropical:)  A firm mountain. (M, A, K.) b2: See also رُسُوبٌ.رَوْسَبٌ A calamity, or misfortune; (K;) as also رَوْسَمٌ. (TA.) مِرْسَبٌ: see رَسُوبٌ.مَرَاسِبُ i. q. أَوَاسٍ [pl. of آسِيَةٌ, and app. here  meaning Columns, or props]. (K.) مُتَرَسِّبٌ: see رَسُوبِىٌّ.