قمس1 قَمَسَ, (S, K,) aor. ـِ and قَمُسَ, (K,) inf. n. قَمْسٌ (S, A, K) and قُمُوسٌ, (TA,) He, or it, (i. e. anything, TA,) dived, or plunged, (S, A, K,) in water: (TA:) he, or it, dived, or plunged, or became immersed, therein, and then rose: (TA:) he (a man) disappeared in water: (Sh:) and ↓ انقمس [signifies the same as قَمَسَ: or] he, or it, became immersed, in water: (S:) and this latter, he leaped into a well. (Sh.) b2: [Hence,] It (a child, or fœtus,) was, or became, in a state of commotion in the belly (S, K) of its mother: (S:) or in the membrane which enclosed it in the belly. (TA.) A2:  قَمَسَهُ, (S, A,) [aor., app., as above,] inf. n. قَمْسٌ, (K,) He immersed, dipped, plunged, or sunk, him or it, (S, A, K, [in the CK القَمْسُ is put by mistake for الغَمْسُ,]) in water; (S, A;) as also ↓ أَقْمَسَهُ, (S,) inf. n. إِقْمَاسٌ. (K.) See also غَمَسَهُ. You say also, قَمَسْتُ بِهِ فِى البِئْرِ I cast him into the well. (Sh.) b2:  قَامَسْتُهُ فَقَمَسْتُهُ: see 3.3 قامسهُ, (K,) inf. n. مُقَامَسَةٌ, (TA,) He vied, or contended, with him in diving. (K, * TA.) You say, ↓ قَامَسَتُهُ قَقَمَسْتُهُ, (S,) [aor. of the latter, accord. to rule, قَمُسَ only,] inf. n. قَمْسٌ, (K,) I vied, or contended, with him in diving, (TA,) and I overcame him therein. (K, TA.) You say of him who contends, disputes, or litigates, with an adversary, (A,) or who disputes with one more knowing than himself, (S, K,) فُلَانٌ يُقَامِسُ حُوتًا (tropical:)  [Such a one vies, or contends, in diving with a fish]. (S, A, K.) You say also, فُلَانٌ يُقَامِسُ فِى سِرِّهِ, meaning, (assumed tropical:)  Such a one hides himself at one time and appears at another. (TA.) 4 ا see 7.A2:  اقمسهُ: see قَمَسَهُ.6 الصِّبْيَانُ يَتَقَامَسُونَ فِى البَحْرِ The children vie, or contend, one with another, in diving in the sea, or great river; syn. يَتَغَاطُّونَ. (A.) 7 ان see قَمَسَ, in two places. b2:  (assumed tropical:)  It (a star) set, or descended in the west; (S, K;) as also ↓ اقمس. (TA.) قَمِيسٌ: see قَامُوسٌ.قَمَّاسٌ: see قَامِسٌ.قَامِسٌ (TA) and ↓ قَمَّاسٌ, (S, TA,) [but the former is a simple epithet, and the latter intensive,] A diver: (S, TA:) a diver for pearls. (TA.) قَوْمَسٌ: see قَامُوسٌ.قَامُوسٌ The sea; syn. بَحْرٌ; (IDrd, K;) as also ↓ قَمِيسٌ: (O:) or the deepest part thereof: (A 'Obeyd, A, K:) or the main body of the water thereof; as also ↓ قَوْمَسٌ: (K, A, TA:) or the middle, and main body, thereof. (S.) مُنْقَمَسٌ The time of a star's setting at dawn. (S, * TA.)