Yoga of course is an umbrella term. It's used in many, many senses. In the Bhagavad Gita if you ask what's yoga, each chapter is a yoga. But what he means by yoga here is yoga maya, that is the power of Brahman, the absolute reality. The power of projecting itself as this universe. That is yoga. As power it is called yoga. And when it manifests themselves as this universe it is called vibhuti. Vibhuti means glory basically, the glory of the Lord.