كوس1 كَاسَ, (S, Msb, K,) aor. ـُ inf. n. كَوْسٌ, (Msb, TA,) He (a camel) walked upon three legs, (S, Msb, K,) being hamstrung: (S, K:) or raised one of his legs, and jumped upon the rest. (TA.) Thus you say of a quadruped: but when said of another, it means, He went upon one leg. (TA.) A2:  كَاسَ, (S, A, TA,) aor. ـُ (S, TA,) inf. n. كَوْسٌ, (A, TA,) He (a man) became turned upside down, (S, TA,) head downwards; (S;) as also ↓ تكوّس. (K.) b2: He (a poor man) fell upon his head. (A, * TA.) A3: كَاسَ فُلَانًا, (K,) aor. ـُ inf. n. كَوْسٌ, (TA,) He prostrated such a one; (K;) as also ↓ اكاسهُ, (K,) inf. n. إِكَاسَةٌ; (TA;) which latter verb is the more chaste: (Sgh:) or he threw him down upon his head; as also ↓ كوّسهُ: (TA:) or this last, which is said of God, (S, A, K,) inf. n. تَكْوِيسٌ, (S, K,) signifies He turned him upside down, (K,) or head downwards, (S,) or upon his head, (A,) فِى النَّارِ in the fire [of Hell]: (S, A:) and you say also, عَلَى رَأْسِهِ ↓ كَوَّسْتُهُ, meaning, I turned him over upon his head. (S.) 2 كَوَّسَ see 1, in three places.4 اكاس البَعِيرَ, (K,) inf. n. إِكَاسَةٌ, (TA,) He made the camel to walk upon three legs, by hamstringing him. (K.) b2:  See also 1.5 تَكَوَّسَ see 1.كَاسٌ: see كَأْسٌ.كُوسٌ A drum: said to be an arabicized word [from the Persian كُوسٌ, pronounced “ kós, ” but in Arabic “ koos, ” and applied in the present day to a kettle-drum; accord. to Golius, a kettle-drum that used to be beaten in the camps and palaces of kings]. (S, K.) [The modern pl. is كُوسَات.]A2:  Hence, A فَرْسَخ [or parasang, or league, in which sense also it is of Persian origin]: because this is the utmost distance at which may be heard the beating of the كوس. (TA.) A3:  Also, A triangular piece of wood with which a carpenter measures the squareness of wood. (Lth, A, * K.) It is [in this sense likewise] a Persian word. (TA.)