It means possessor of notches or the Lord of the vertebrae of the back. It was the name borne by a famous sword owned in turn by a pagan called al-As bin Munabbih, who was killed in the battle of Badr. The Prophet acquired it in a booty and presented to Ali bin Abu Talib. The expression of zulfikar (dhu'l fiqar or dhu'l faqar) is explained by the presence of this sword of notches (fukra) or grooves. It was double-edged (shafratani) and its blade was strengthened in the middle by a pole (amud). According to a tradition the sword contained inscription, la yuktal muslim bi-kafir means "No Muslim shall be slain for an unbeliever."
In the battle of Uhud, Ali fought valiantly in the field, the Prophet glorifies his valour and the words gushed out of his mouth, "There is no hero like Ali, and there is no sword like the zulfikar."
Mohammad al-Farsi writes in Shafa al-gharam bi-akhbar al-balad al-haram (Leipzig, 1858, p. 208) that, "In 401/1010, the amir of Mecca gave the khutba in the name of Imam al-Hakim. The amir also claimed to possess Zulfikar as well as the rod (qadib) of the Prophet." The sword relic was shown by a description from Fatimid period, vide al-Majalis wa'l Musayarat (Tunis, 1978, p. 114) by Qadi Noman.
The Mystical Poems of Ibn al-Farid (Dublin, 1956, 13:54) quotes following verse: Dhu'l fiqari l-lahzu minha abadan, Wa-l hasha minniya amrun wa-huyai means "Zulfikar is ever the cutting glance of her, and my poor heart is as Amr and Huyai." It is to be noted that Amr and Huyai were the victims of Ali in the battle.
Ibn Hani (d. 362/973) in his Diwan Ibn Hani al-Andalusi (ed. Zahid Ali, Cairo, 1933) says:- "He came bearing with him the splendour of the sword Zulfikar as if he were adorned with its belt"
Nasir Khusaro also mentions in his Diwan (ed. N. Taqavi, Tehran, 1925) that, "The Koran and the pure sword of Haidar