عرمضQ. 1 عَرْمَضَ, inf. n. عَرْمَضَةٌ and عِرْمَاضٌ, (Lh, O, K,) It (water) became overspread with عَرْمَض [q. v.]; (Lh, O;) i. q. طَحْلَبَ. (K.) عَرْمَضٌ (Lth, S, O, K) and ↓ عِرْمَاضٌ (IDrd, K, TA, written in the O عَرْمَاض) i. q. طُحْلُبٌ; (S, O, K;) i. e. The green substance that comes forth from the bottom of water, so as to overspread it; (S, O, L;) also called ثَوْرُ المَآءِ; [O; in the L, and in one copy of the S, ثَوْبُ المَآءِ, which is a mistake;] accord. to Az; (S, O;) the green substance like خِطْمِىّ [or marsh-mallow], which is upon water; (Lh;) a soft green substance, like loosened and separated wool, upon stale water; so says Lth, and he adds his opinion that it is vegetative: (TA:) n. un. with ة. (K.) b2: Also the former, (O, K,) and ↓ عِرْمِضٌ, (El-Hejeree, K,) A sort of trees, of those called عِضَاه, (Lth, O, K,) having thorns like the beaks of birds; the hardest thereof in the wood: (Lth, O:) or the former, (O, K,) as some assert, (AHn, O,) the small of the أَرَاك (AHn, O, K) and of the سِدْر and of all trees that never become great: (K:) or small trees of those called سِدْر, that do not become large nor tall, of which the thorns are like the beaks of birds; the hardest thereof in the wood, and the best for bows: (IAar, O:) or certain small trees: or the small of the عِضَاه: or the small of all trees: n. un. with ة. (O.) عِرْمِضٌ: see the next preceding paragraph.عِرْمَاضٌ inf. n. of 1: b2:  and i. q. عَرْمَضٌ, q. v.مَآءٌ مُعَرْمِضٌ [so in the TA, agreeably with the verb; but in my two copies of the S, مُعَرْمَضٌ;] Water overspread, or becoming overspread, with عَرْمَض. (S, TA.)