Mool Mantra is the opening verse of Sri Guru Granth Sahib Ji. The word Mool (Mul) means root, primordial, basis or foundation. Mantra (mantar) means a sacred formula or a combination of sacred words. So the mool mantar is the root mantra that forms the basis of the holy granth.

ORIGIN OF MOOL MANTRA

Guru Nanak Dev Ji revealed the mool mantar for the first time at Gurudwara Sant Ghat Sahib which is situated in Kapurthala district of Punjab. Gurudwara Sant Ghat Sahib is the place located on the bank of river Bein (Vein), where Guru Nanak dev Ji re-emerged after 3 days of his disappearance at the site of Gurudwara Shri Ber Sahib.

MEANING OF MOOL MANTRA (MUL MANTAR)

The opening verse of Guru Granth Sahib ji that was authored by Guru Nanak , is considered as the basis of Sikhi. What we call as Mool Mantra is Guru Nanak’s description or definition of God. What Guru Nanak is trying to say in these few words are the different qualities or virtues of God. The meaning of this verse is philosphically dense, extremely difficult to put in few words as it encloses the essence of the spiritual message of Guru Granth Sahib Ji (1430 Ang).

Let us try to have a look at what Guru Nanak Sahib is trying to tell us, word by word.
ੴ – means One Supreme Reality. By adding the numerical ੧ in the beginning, Guru Nanak Dev Ji tries to tell us that there is only one without the second. Oankaar – means that the One supreme reality (God) constantly manifests itself throughout the entire creation in various forms. Oankaar is present everywhere.
Satnam – means that the name of God is true & everlasting.
Karta Purakh – Karta translates to the doer or the creator. Other meaning of Karta is “the act of doing”. Purakh refers to the universal being that is submerged in its own creation. So Karta Purakh means the universal being that does everything.
Nirbhau Nirvair – Nirbhau means without fear and Nirvair means without hatred. Nirbhau Nirvair being the quality of that universal being, here states that God is not afraid of anyone and he does not holds any hatred or ill-will against anybody.
Akaal Moorat – Akaalmoorat means beyond time, death and form. The word Akaalmoorat refers to the God being an eternal formless insdestructible entity.
Ajooni – Ajooni means beyond birth or existence. The word Ajooni refers to the quality of God that the supreme being is beyond incarnation.
Saibhang – Saibhang means self-existing. The word Saibhang is derived from sanskrit words – Swayam (self) + Bhoo (existent). Saibhang is the power of the God which means that it is self creating, it exists by itself without any cause.
Gurparsad – Guru refers to the master who is the dispeller of ignorance. Parsad refers to the master’s favour or grace. Here Gurparsad refers to that the God can be known or realised by the true Guru’s grace.
Jap – To meditate.
Aad Sach Jugaad Sach – Aad Sach means true in the primal beginning & Jugaad Sach means true throughout the ages. Meditate on that universal being who was true in the beginning & still is throughout the ages.
Hai Bhi Sach, Nanak Hosee Bhi Sach – Hai Bhi Sach means True in this instant.

Nanak Hosee Bhi Sach means O Nanak, forever and ever true.

Mool Mantra – Sometimes Mool Mantra is also spelt as Mool Mantar or Mul Mantra.