غسم1 غَسَمَ It (the night) was, or became, dark; (As, S, K;) as also ↓ اغسم, (JK, K,) like أَغْسَى. (JK.) 4 أَغْسَمَ see what precedes.غَسَمٌ The darkness (S, ISd, TA) of night; (ISd, TA;) like غَسَقٌ: (S, TA:) or blackness: (Kr, K:) and (K) accord. to En-Nadr, (S,) the confusedness, or blending, of the darkness: (JK, S, K:) and the first rising of the dawn. (JK.) b2:  And Dust, or dust rising, or spreading, like smoke; syn. هَبْوَةٌ and غَبَرَةٌ (K) or غُبْرَةٌ [which sometimes signifies the same as غَبَرَهٌ]. (CK.) غُسَمٌ; see أَغْسَامٌ.لَيْلٌ غَاسِمٌ Dark night. (TA.) فِى السَّمَآءِ أَغْسَامٌ and ↓ غُسَمٌ In the sky are portions of clouds. (K.) غسو and غسى 1 غَسَا اللَّيْلُ, (S, K,) aor. ـْ (S,) inf. n. غُسُوٌّ; (S, K; accord. to some copies of the K غَسْوٌ;) and غَسَى, aor. ـْ (IJ, TA;) and غَسِىَ, aor. ـْ (S, K, TA,) inf. n. غَسًا; of which last form, غَشِىَ is a dial. var.; (TA;) The night was, or became, dark; as also ↓ اغسى. (S, K.) [See also عَسَا.]4 أَ1ْ2َ3َ see what precedes. b2:  اغسى also signifies He (a man) entered upon the time of, or a little after, sunset. (TA.) b3:  And أَغْسِ مِنَ اللَّيْلِ Journey thou not in the first part of the night, until its darkness depart. (TA.) A2:  And اغساهُ اللَّيْلُ The night enveloped him in its darkness. (Sgh, K.)