Ik onkar is a fundamental concept in Sikhism, meaning 'There is only one God.' It emphasizes the monotheistic belief central to both Sikhism and certain aspects of Hinduism, reflecting a shared spiritual heritage. This phrase serves as a cornerstone of Sikh teachings and encapsulates the belief in the unity of God, which connects Sikhism to the broader context of Hinduism through shared philosophical themes such as the nature of divinity and the quest for spiritual truth.