ثعب1 ثَعَبَهُ, (S, A, K,) aor. ـَ (K,) inf. n. ثَعْبٌ, (S,) He gave vent to it; or made it to flow forth, run, or stream; namely, water, (S, A, K,) and blood, and the like. (K.) ثعب دَمًا, [thought by MF to be ثَعَبَ, but I see no reason why it should not be ثَعَبَ,] said of a wound, means It flowed, or ran, with blood. (TA.) 7 انثعب It (water) had vent; or it flowed forth, ran, or streamed; (S, A, K;) in, or through, a مَثْعَب: (S TA:) and in like manner, rain: (TA:) and blood from the nose. (S, TA.) b2:  [Hence,] صَاحَ بِهِ فَانْثَعَبَ إِلَيْهِ (tropical:)  He called out to him and he sprang up and ran to him. (A, TA.) ثَعْبٌ, applied to water, (K,) and to blood, (TA,) Flowing, running, or streaming; as also ↓ ثَعَبٌ and ↓ أُثْعُوبٌ and ↓ أُثْعُبَانٌ. (K, TA.) Yousay ↓ سَيْلٌ أُثْعُوبٌ [A flowing torrent]. (A.) b2: And [hence,] ↓ شَرٌّ أُثْعُوبٌ (tropical:)  [Evil that takes its course like a stream]. (A.) b3:  See also what next follows.ثَعَبٌ, (so in the S, expressly said to be بِالتَّحْرِيكِ,) or ↓ ثَعْبٌ, (so in the K,) in some copies of the K, erroneously, مَثْعَب, (TA,) A water-course of a valley; a channel in which water flows in a valley: (S, K:) accord. to Lth, the rubbish and scum that collect in the channel in which the rainwater flows; but Az disapproves of this explanation of the word, and says that it signifies, in his opinion, the channel itself: (TA:) the pl. is ثْعْبَانٌ. (S, K.) One says, سَالَتِ الثُّعْبَانُ كَمَا سَالَ الثُّعْبَانُ, i. e. The torrent [or rather the torrents ran like the serpent called ثعبان]. (A, TA.) b2: See also ثَعْبٌ.ثُعْبَانٌ A kind of long serpent: (S:) a great serpent; applied to the male and the female: (Msb:) a bulky and long serpent, (Sh, K, TA,) that hunts the rat or mouse, to which latter animal the name is sometimes metaphorically applied, and that is more useful in the house than are cats: (Sh, TA:) or particularly the male [serpent], (Ktr, K,) that is yellow, and ruddy: (Ktr:) or the serpent in general, (ISh, K,) male and female, great and small: (ISh:) [also applied to an enormous fabulous serpent; described by Kzw and others:] pl. ثَعَابِينُ. (S, Msb.) b2:  [رَئيِسُ الثَّعَابِينِ The basilisk. (Golius, from a Glossary.)]b3:  دَمُ الثُّعْبَانِ: see دَمٌ.فُوهُ يَجْرِى ثَعَابِيبَ, (As, S, K,) or فَمُهُ, (TA,) and سَعَابِيبَ, (S,) His mouth runs with clear water, having an extended [or a ropy] flow. (As, S, K.) أُثْعُبَانٌ: see ثَعْبٌ.أُثْعُوب: see ثَعْبٌ, in three places.مَثْعَبٌ [The outlet, or place of outpouring, of the water of a watering-trough &c.;] the place of passage for the water, in the side of a wateringtrough or tank: and a channel, or conduit, for water: (KL:) pl. مَثَاعِبُ. (S, A.) You say مَثْعَبُ الحَوةَ [The outlet for the water of the watering-trough or tank]: (S, A:) and مَثْعَبُ السَّطْحِ [the outlet for the water of the house-top]: (A:) and مَثْعَبُ المَطَرِ [the outlet, or channel, for the rain-water]: (TA:) from ثَعَبَ المَآءَ “he gave  vent to the water,” or, “made it to flow forth,”&c. (A, TA.) And مَثَاعِبُ المَدِينَةِ, meaning The channels, or places of flowing, of the water of the city: (K, TA:) whence it appears that MF has erred in saying that مَثْعَبٌ signifies [only] a مِزْرَاب [or spout for conveying away water from a housetop &c.]: not a channel, or place of flowing. (TA.) [See also صُنْبُورٌ, and لَوْلَبْ.]