“Yoga Meditation is the art and science of systematically observing, accepting, understanding, and training each of the levels of our being, such that we may coordinate and integrate those aspects of ourselves, and dwell in the direct experience of the center of consciousness. The links above are to a 16-page description of Yoga Meditation, which explains the process in practical terms, and simple language.

Yoga Meditation is not actually a separate aspect of Yoga, due to the fact that Yogais meditation. However, the phrase Yoga Meditation is being used here to discriminate between Yoga Meditation and the now popular belief that Yoga is about physical postures. Yoga or Yoga Meditation is a complete process unto itself, only a small, though useful part of which relates to the physical body. (See the article Modern Yoga versus Traditional Yoga)”

Reference: http://www.swamij.com/yoga-meditation.htm