Yogas chitta vritti nirodh: Yoga is the neutralization of the waves of thought and/or feeling.
I am always attracted to imagery that includes water, waves, and streams. I have been drawn to the energy of the ocean since I was a child growing up in the South. I feel it. I understand it. I exchange energy with the gentle in-breath and out-breath of the universe that comes through the movement of the water in the ocean. This is why I enjoy this translation of one of Patanjali's Yoga Sutras, shared by Swami Kriyananda and paraphrased by me.
Chitta is often translated as thought or feeling, "mind-stuff", "consciousness", "sub-consciousness", or the "lower mind".
Paramhansa Yogananda expresses that the waves in the mind which produce delusion and bondage are primarily the likes and dislikes, the biased feelings of the heart. Vritti can be translated as vortices or whirlpools~ whirling eddies that interfere with life's smoothly flowing stream, sucking into a purely private orbit whatever one likes, making one so preoccupied with egoistic selections and rejections that s/he is not longer consciously part of the stream or flow of universal energy.
What ceases when practicing yoga are waves, or eddies, of selfish likes and dislikes of attachment. Here we enter into the sacred life-stream of Pranava, or AUM, and merge consciously into the silent, infinite ocean of Spirit.
Yoga is the neutralization of ego-directed feelings, because once these become stilled or quiet (think the stillness and glassy surface of a mountain lake), the practitioner realizes that s/he is (and has always been) one with the Infinite and that his or her awareness of this reality was limited by his or her own infatuation with thoughts/limitation.
This is a goal of all paths of yoga, to quiet or still the activity of the mind, so that we may experience divine calmness and connection with the Infinite.