Trunk, stem, or stump of a palm tree.
‘A’jaz al-nakhl is the stump and the main stem of the date palm tree. ‘Aslu al-nakhl is the bottom of a palm tree from which the fibrous roots protrude. When the palm tree is healthy and active, the trunk of the tree will have a solid core. Al-jidh’ is the singular of judhū’ al-nakhl, used to represent the cylindrical part (trunk or stem) of the palm tree, above the soil’s surface. The botanical term ‘A’jaz khāwiyah refers to the hollow base or trunk of the date palm tree. It occurs when a palm tree dries out, and its base or trunk (‘A’jaz) grows hollow because the cells have withered.
The term ‘A’jaz khāwiyah is mentioned in the Holy Qur’an. Allah, the merciful, the compassionate, says: “He made it rage against them seven nights and eight days in succession: so that thou could see the (whole) people lying prostrate in its (path), as they had been roots of hollow palm trees tumbled down!” Surat Al Haaqqa, Verse 7.
Narrated by Jabir bin `Abdullah:The Prophet used to stand by a stem of a date-palm tree (while delivering a sermon). When the pulpit was placed for him we heard that stem crying like a pregnant she-camel till the Prophet got down from the pulpit and placed his hand over it. Sahih Al Bukhari, book of Friday Prayer.