Cute Young Brunette Girl Practicing Yoga Poses

Patanjali is widely regarded as the founder of the formal Yoga philosophy. Patanjali's yoga is known as Raja yoga, which is a system for control of the mind. Patanjali defines the word "yoga" in his second sutra, which is the definitional sutra for his entire work:
योग: चित्त-वृत्ति निरोध:
(yogaś citta-vṛtti-nirodhaḥ)