ثعب

ثَعَبٌ ثعب , (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.