مءه

مَاهِيَّةٌ ذ [The quiddity, or essence, or substance, of a thing;] that whereby a thing is what it is. (KT.) See also حَقِيقَةٌ, and جَوْهَرٌ, and ذَاتِيَّةٌ, and مَعْنًى.