Onkar means the divine creative force or universal sound, symbolizing the eternal presence of God. In Sikhism, it appears in "Ik Onkar", meaning "There is only One God."
Meaning of Ik Onkar : One God In Sikhism | Sikhi Teachings
The phrase “ Ek Onkar ” is a merging of two words: “ Ek,” meaning “ One, ” and “ Onkar,” referring to the creative force, the Divine itself. It’s a simple statement of existence – an affirmation that our lives and all creation are knotted in oneness.
Meaning of Ek Onkar - Sikhism - Sikh History, Culture & Philosophy
On the other hand, Nanak refers to God as Onkar, 'the expression of Om', that is, of the sacred syllable of the Hindus, a conception that actively continues as Ik Onkar, 'the one om expression'.
According to Sekhon: “ੴpronounced as “Ikk Onkar” “Ek Onkar” or as “Ekunkar” is the most fundamental belief of Sikhism, and the contents of the whole Sri Guru Granth Sahib revolve around it. It signifies that there is only one Supreme Being in the universe, which is also the creator of the universe.
The Ik Onkar, also written as Ek Onkar, is a phrase outlining one of the most important tenets of Sikhism. It can be seen on Sikh temples and even features as the first words of the Mul Mantar, the opening words of the holy scripture of the Sikh faith.
Ek Onkar forms the cornerstone of Sikh belief in the unity and oneness of God. Ek Onkar is the beginning of the Sikh Mool mantra, and the first phrase in the Sikh Holy book, the Guru Granth Sahib: There is but one God. Truth by name, the creator, all-pervading spirit, without fear, without enmity.