Definition - What does Guru Om mean?
Guru om is a mantra composed of two significant words in yoga and Indian philosophy. Guru is a term that describes a spiritual leader or teacher. Om (also spelled aum) is the sound of the cosmic vibration and is an element in many mantras chanted silently or aloud. Guru om, therefore, invokes both the energy of the universe and the wisdom of the guru.
Yogapedia explains Guru Om
Derived from the Sanskrit word, gu, which means “darkness,” and ru, which translates as “remover,” the guru is more than just a teacher, but someone who removes spiritual darkness and paves the way to enlightenment and unity with Brahman. Om is the sound that represents Brahman, the universe and essence of creation. Guru om can be chanted by itself, as part of a longer mantra or hymn, or as individual components in a mantra.