I.2 - yogaḥ cittavṛttinirodhaḥ

What is Yoga? It is a word that has many interpretations and connotations.  Patañjali defines his understanding of this word. 

Yoga is the ability to immerse the mind exclusively towards an object of focus and sustain this connection without any distractions. 

The object of focus can be a concrete one, either external to ourselves or part of ourselves. It can be an area of interest, a concept or something beyond the grasp of the senses, such as God.