أُسٌّ
1.
The foundation, basis, or lowest part, (S, A, Mgh, Msb, K,) of a building, (S, A, K,) or of a wall; (Mgh, Msb;) as also
أَسٌّ and
إِسٌّ (A, K) and
أَسَاسٌ (S, A, Mgh, Msb, K) and
أَسَسٌ, (S, K,) which is a contraction of أَسَاسٌ: (S:) or the commencement of a building: and any commencement of a thing; as also
أَسٌّ and
أَسَاسٌ and
أَسَسٌ: (M:) and the origin, source, stock, or root, (أَصْل,) of a man; as also
أَسٌّ: or of anything; (M, K;) as also
أَسٌّ (M, K) and
إِسٌّ and
أَسِيسٌ: (K:) and the heart of a man; because [the Arabs believe that] it is the first thing that comes into existence in the womb: (M, K:) plural اسَاسٌ (S, M, Mgh, Msb, K) and إِسَاسٌ (M, Msb, K) and أُسُسٌ; (M, Mgh, Msb, K;) the first of which is plural of أٌسٌّ, (Mgh, Msb,) like as أَقْفَالٌ is of قُفْلٌ; (Msb;) or of أَسَسٌ, like as أَسْبَابٌ is of سَبَبٌ; (S;) or, as some say, of أُسُسٌ, [like as أَعْنَاقٌ is of عُنُقٌ,] so that it is a plural plural; (TA;) and the second, of أَسٌّ, like as عِسَاسٌ is of عُسٌّ; (Msb;) and the third, of أَسَاسٌ, (Mgh, Msb,) like as عُنُقٌ is of عَنَاقٌ. (Msb.) You say, الأَوَّلِ
بَنَى بَيْتَهُ عَلَى أَسَاسِهِ [He built his house upon its first foundation.] (A.) And قَلَعَهُ مِنْ أُسِّهِ [He uprooted it from its foundation]. (A.) And أَمْرِهِ الكَذِبُ
فُلَانٌ أَسَاسُ (tropical:) [Such a one, the foundation of his affair, or case, is falsehood]. (A, TA.) And كَانَ ذٰلَكَ عَلَى أُسِّ الدَّهْرِ, (S, M, A, K,) and
أَسِهِ, and
إِسِهِ, (S, M, K,) (tropical:) That was in old, or ancient, time; (S, M, K;) at the beginning of time; (S, A, * K;) and in like manner, عَلَي اسْتِ
الدَّهْرِ. (A.)
2.
Also A remain, relic, trace, vestige, sign, mark, or track, of anything. (K.) You say, خُذْ أُسَّ الطَّرِيقِ, or الطَّرِيقِ
أَسَّ, [according to different copies of the K, meaning, Take thou to the track of the way,] when one guides himself by any mark or track, or by camels' dung: but when the way is manifest, you say, خُذْ شَرَكَ الطَّرِيقِ. (K.) أُسٌّ also signifies The remains of ashes (M, K) between the
أَثَافِى, q.v.: (M:) occurring in a verse of En-Nábighah Edh-Dhubyánee; but according to most relates of this verse, it is اسٌ. (TA.)