كَثِيبٌ
1.
A thing collected together. (Msb.)
2.
A hill, or heap, of sand: (S, K:) or an oblong and gibbous hill of sand: or an extended gibbous hill [or an elevated expanse] of sand: or what has collected, of sand, and assumed a gibbous shape: (TA:) or what has poured down, of sand, into a place, and collected there: (S:) [less than what is called عَقَنْقَلٌ, q. v.:] plural كُثْبَانٌ (S, K) and كُثُبٌ and أَكْثِبَةٌ: (K:) [the last a plural of pauc.].
3.
وكَانَتِ الجِبَالُ كَثِيبًا مُهِيلًا [Qur'an, 73:14,] signifies And the mountains shall be sand, whereof the lower part being shaken, it shall pour down upon thee from above. (Fr.)
4.
ثَلَاثَةٌ عَلَى كُثُبِ المِسْكِ, or كُثْبَانِ المسك, [Three (descriptions of men shall be, on the day of resurrection,) on hills, or heaps, of musk]. (TA, from a tradition)