Core sense — continuing without end; continuance of time, of night or of daygenerated
1
Signifies, or implies, continuance, or incessant continuance, دَوَام and اِتِّصَال, of time, either of night or of day.
[I have said “or implies” because I have not found it used otherwise than as an adjective, in the senses that follow.]
1.1
Continuing; or continuing incessantly, or endlessly; synonymous with دَائِمٌ or دَائِمٌ لَا يَنْقَطِعُ.
Applied in this sense to night [and also to day: to each in the Qurʾān 28:71 and 72]; and to night as meaning long.
Qur’ān 28:71 approximate — somewhere between 28:45 and 28:88 Lane cites “Kur xxviii. 71”
Qur’ān 28:71 the verse Lane’s citation points to, and it uses this root
قُلْ أَرَءَيْتُمْ إِن جَعَلَ ٱللَّهُ عَلَيْكُمُ ٱلَّيْلَ سَرْمَدًا إِلَىٰ يَوْمِ ٱلْقِيَـٰمَةِ مَنْ إِلَـٰهٌ غَيْرُ ٱللَّهِ يَأْتِيكُم بِضِيَآءٍ ۖ أَفَلَا تَسْمَعُونَSay: See ye? If Allah were to make the night perpetual over you to the Day of Judgment, what god is there other than Allah, who can give you enlightenment? Will ye not then hearken?Abdullah Yusuf Ali, The Holy Qur’ān (1934)
1.2
According to El-Fakhr Er-Rāzee, it is derived from السَّرْدُ, which denotes coming one after another without a break, and the م is added to strengthen the meaning.
If so, its proper place is in the article سرد, its measure being فَعْمَلٌ, and its م is added, like the م in دُلَامِصٌ.
Lane cites “Bd in xxviii. 71” — a commentary, not the verse; no modern number is given
1.3he, or it, is yours ever, or for ever—هُوَ لَكَ سَرْمَدًا
Mentioned in the article سمد.
Qur’ānic occurrences سَرْمَد
28:71
قُلْ أَرَءَيْتُمْ إِن جَعَلَ ٱللَّهُ عَلَيْكُمُ ٱلَّيْلَ سَرْمَدًا إِلَىٰ يَوْمِ ٱلْقِيَـٰمَةِ مَنْ إِلَـٰهٌ غَيْرُ ٱللَّهِ يَأْتِيكُم بِضِيَآءٍ ۖ أَفَلَا تَسْمَعُونَSay: See ye? If Allah were to make the night perpetual over you to the Day of Judgment, what god is there other than Allah, who can give you enlightenment? Will ye not then hearken?
28:72
قُلْ أَرَءَيْتُمْ إِن جَعَلَ ٱللَّهُ عَلَيْكُمُ ٱلنَّهَارَ سَرْمَدًا إِلَىٰ يَوْمِ ٱلْقِيَـٰمَةِ مَنْ إِلَـٰهٌ غَيْرُ ٱللَّهِ يَأْتِيكُم بِلَيْلٍ تَسْكُنُونَ فِيهِ ۖ أَفَلَا تُبْصِرُونَSay: See ye? If Allah were to make the day perpetual over you to the Day of Judgment, what god is there other than Allah, who can give you a night in which ye can rest? Will ye not then see?
Occurrences of this form in the Qur’ān, not Lane’s choice of verse. They show the word in use; they do not say which sense above applies. Where more occur than are shown, the shortest āyāt are chosen.
Show Lane's original text
[signifies, or implies,] Continuance, or incessant continuance, ( دَوَام , Kh, M, L, and اِتِّصَال , Kh, L,) of time, (Kh, M, L,) either of night or of day. (Kh, L.) [I have said “ or implies ” because I have not found it used otherwise than as an epithet, in the following senses.] Continuing; or continuing incessantly, or endlessly; syn. دَائِمٌ ; (Zj, S, L, K;) or دَائِمٌ لَا يَنْقَطِعُ . (Nh, L.) It is applied in this sense to night (Nh, L) [and also to day: to each in the Kur xxviii. 71 and 72]: and to night as meaning Long. (L, K.) Accord. to El-Fakhr Er-Rázee, it is derived from السَّرْدُ , which denotes consecutiveness and uninterruptedness, and the م is added to give intensiveness to the signification: if so, its proper place is in art. سرد ; its measure being فَعْمَلٌ : (MF:) [thus] its م is augmentative like the م in دُلَامِصٌ . (Bd in xxviii. 71.) One says also, هُوَ لَكَ سَرْمَدًا He, or it, is thine ever, or for ever. (Mgh in art. سمد .)