قوس1 قَاسَ الشَّىْءَ بِغَيْرهِ, and عَلَى غَيْرِهِ, aor. ـُ inf. n. قَوْسٌ (S, K *) and قِيَاسٌ, (S,) i. q. قَاسَهُ, aor. ـِ inf. n. قَيْسٌ (S, K *) and قِيَاسٌ; (S;) i. e., He measured the thing by another thing like it; [both in the proper sense and mentally; but the latter verb is the more common, though the former, accord. to the JK, is the original;] (S, TA;) and so الشَّىْءَ بِغَيْرِهِ ↓ اقتاس: (S, K: *) but you should not say ↓ أَقَسْتُهُ for قُسْتُهُ or قِسْتُهُ. (S.) A2:  قَوِسَ: see 5.2 قَوَّسَ see 5, in two places.A2:  قوّسهُ, inf. n. تَقْوِيسٌ, He made it bowed, or bent. (KL.) 4 أَقْوَسَ see 1: A2:  and see 5.5 تقوّس It (a thing) became bowed, or bent; as also ↓ است (TA:) the ↓ latter is also said, tropically, of the moon when near the change [&c.]. (A, TA.) b2:  (tropical:)  He (an old man, S, A) became bowed, or bent; (A, * K;) as also ↓ قَوَّسَ, inf. n. تَقْوِيسٌ; (S, A, * Msb, K;) and ↓ استقوس; (S;) and ↓ ا (A:) or he became bowed, or bent, in the back; as also ↓ قَوَّسَ; and ↓ استقوس; (TA;) and so ↓ قَوِسَ, aor. ـَ inf. n. قَوَسٌ. (K.) A2:  تقوّس قَوْسَهُ He put his bow upon his back. (TA.) 8 إِقْتَوَسَ see 1. b2:  يَقْتَاسُ بِأَبِيهِ, (S, K,) inf. n. إِقْتِيَاسٌ, (S,) (assumed tropical:)  He follows the way of his father, and imitates him. (S, K.) 10 إِسْتَقْوَسَ see 5, in four places.قَاسُ رُمْحٍ: see قِيسُ رُمْحٍ.قَوْسٌ [A bow;] a certain thing, well known, (A, K,) with which one shoots: (M, TA:) of the fem. gender: (IAmb, M, Msb:) or masc. and fem.: (S, Msb:) or sometimes masc.: (A, K:) pl. [of pauc.] أَقْوَاسٌ (IAmb, S, A, Msb, K) and أَقْيَاسٌ, (TA, and so in some copies of the K, in the place of the former,) the ى being interchangeable with the و, (TA,) and [of mult.] قِسِىٌّ, (S, A, Msb, K,) originally قُوُوسٌ, (S, TA,) which is not used, (TA,) of the neasure فُعُولٌ, (S, Msb,) first changed to قُسُوٌّ, of he measure فُلُوعٌ, and then to قِسِىٌّ, of the measure فِلِيعٌ, like عِصِىٌّ, (S,) and قُسِىٌّ, (Fr, Sgh, K,) from the same original, (TA,) [like عُصِىٌّ,] and قِيَاسٌ, (IAmb, S, A, Msb, K,) which is more agreeable with analogy than قسىّ. (TA.) The dim. is قُوَيْسٌ, (IAmb, M, Msb, K,) without ة, contr. to rule, as the word is fem., (M, TA,) and قُوَيْسَةٌ, (IAmb, Msb, K,) sometimes: (IAmb, Msb:) or the former accord. to those who make قوس to be masc., (S,) and the latter accord. to those who make it to be fem. (S, Msb.) It is prefixed to another word to give it a special signification. Thus you say, قَوْسُ نَبْلٍ An Arabian bow. And قَوْسُ نُشَّابٍ A Persian bow. And قَوْسُ حُسْبَانٍ [A bow for shooting a certain kind of short arrows]. and قَوْسُ جُلَاهِقٍ [A cross-bow]. And قَوْسُ نَدْفٍ [A bow for loosening and separating cotton]. (Msb.) b2:  [Hence the saying,] فُلَانٌ لَا يَمُدُّ قَوْسَهُ أَحَدٌ [Such a one, no one will pull his bow;] i. e., (tropical:)  no  one will vie with him, or compete with him. (A, TA.) And رَمَوْنَا عَنْ قَوْسٍ وَاحِدٍ, (A, TA,) or وَاحِدَةٍ, (Mgh,) [lit., They shot at us from one bow: meaning, (tropical:)  they were unanimous against us;] a proverb denoting agreement. (Mgh.) [In the Msb, رَمَوْهُمْ and وَاحِدَةٍ.] And هُوَ مِنْ خَيْرِ قُوَيْسٍ سَهْمًا; (S, L, K; except that in the L and K, for قويس, we find قَوْسٍ;) (tropical:)  [He is of the best of a little bow, as an arrow; i. e., he is one of the best arrows of a little bow;] or صَارَ خَيْرَ قُوَيْسٍ سَهْمًا (A, K) (tropical:)  [He became the best of a little bow, as an arrow; i. e., he became the best arrow of a little bow:] a proverb [See Arab. Prov. i. 718] applied to him who has become mighty after being of mean condition: (A:) or to him who opposeth thee and then returns to doing what thou likest. (A, K.) [Hence also the phrase in the Kur, liii. 9,] فَكَانَ قَابَ قَوْسَيْنِ And he was at the distance of two Arabian bows: or two cubits [this is app. an explanation by one who holds قَابَ قَوْسَيْنِ to be for قَابَىَ قَوْسٍ:] (K:) or the meaning is, قَابَىْ قَوْسٍ, i. e., [at the distance of the measure of] the two portions between the part of a bow that is grasped by the hand and each of the curved extremities. (TA.) See also art. قوب. b3:  القَوْسُ (assumed tropical:)  [The Sign of Sagittarius; also called الرَّامِى;] one of the signs of the zodiac; (S, K;) namely, the ninth thereof. (TA.) b4:  قَوْسُ قُزَحَ The rainbow: the two words are inseparable. (TA.) See قزح. b5:  قَوْسُ الرَّجُلِ (assumed tropical:)  The bowed, or bent, part of the back of a man. (IAar.) b6:  أَقْوَاسُ البَعِيِر (tropical:)  The anterior ribs of the camel. (A.) b7:  Also قَوْسٌ (tropical:)  What remains, of dates, (S, A, * K,) in the [receptacle called] جُلَّة, (S,) or in the bottom thereof, (K,) or in the sides thereof, like a bow: (A:) or, accord. to Zeyd Ibn-Kuthweh, the fourth part of the جُلَّة, of dates; like رِزْمَةٌ: (TA in art. رزم:) in this sense, also, it is fem.: or a number of dates collected together: pl. as above. (TA in the present art.) A2:  Also, A cubit: (S, K:) sometimes used in this sense: (S:) because a thing is measured (يُقَاسُ) with it. (K.) قِيسُ رُمْحٍ and قَاسُ رُمْحٍ The measure of a spear. (Msb, in this art.; and S, K, in art. قيس.) قَوَّاسٌ A hewer, or fashioner, of bows; and so, perhaps, قَيَّاسٌ. (TA.) قُسَوِىٌّ is the rel. n. from قِسِىٌّ, [pl. of قَوْسٌ,] because it is [before its last change] of the measure فُلُوعٌ changed from the measure فُعُولٌ. (S.) أَقْوَسُ Having a bowed, or bent, back. (S, K.) b2:  Sand that is elevated (K, TA) like a hoop or ring. (TA.) مِقْوَسٌ A bow-case. (S, K.) A2:  A horse-course; a race-ground: (Ibn-'Abbád, K:) a place whence horses run (K) for a race; (TA;) i. e., (so in the K accord. to the TA,) a rope at which the horses are placed in a row (S, A, K) on the occasion of racing, (S, K,) in the place whence they run: (A:) or the extended rope from which the horses are started: (JK:) also called مقيص: the pl. is مَقَاوِسُ. (TA.) Hence the saying, عُرِضَ فُلَانٌ عَلَى المِقْوَسِ [Such a one has been put to the starting-rope]; meaning, (tropical:)  such a one has been tried, or proved, by use, practice, or experience. (A, TA.) And فُلَانٌ عَلَى مِقْوَسٍ, i. e., عَلَى حِفَاظٍ[app. meaning, (assumed tropical:)  Such a one is intent upon defending his honour or the like]. (Lth, L.) مُقَوَّسٌ and مُقَوِّسٌ: see مُتَقَوِّسٌ.مُتَقَوِّسٌ (assumed tropical:)  An eyebrow [or other thing] likened to a bow; as also ↓ مُسْتَقْوِسٌ (K) and ↓ مُقَوَّسٌ: (TA:) ↓ the second of these epithets is also applied, in the same sense, or like a bow, to a gutter round a tent, and the like. (TA.) b2:  Also, A man bowed, or bent; and so ↓ مُقَوِّسٌ. (TA.) A2:  Also, (K,) or مُتَقَوِّسٌ قَوْسَهُ, (S,) A man having with him his bow. (S, K. *) مُسْتَقْوِسٌ: see مُتَقَوِّسُ, in two places.