A line from Patanjali's Yoga Sutras, "yogas chitta vritti nirodha" refers to stilling the mind in order to experience Ultimate Reality and move toward Self-realization.
Yogas chitta vritti nirodha is Patanjali’s definition of yoga. It means that yoga is the removing of the fluctuations of the mind.
Yoga is the stilling of the mind until it rests in a state of total and utter tranquility, so that one experiences life as it is: as Reality.
One experiences life through the clearest of lenses — lenses not colored by thoughts of good or bad, or mine or yours. When the fluctuations of the mind are totally removed, we are at one with everything and all that is.