Yoga means union – union between the body and the soul, the human and the divine, the finite and the infinite.
In the West Yoga is considered to be the same as Hatha-Yoga. Hatha Yoga is a beginner level of a Yoga path, where body and psyche can relax.
Meditation also is a part of Yoga. It is the technique to control the mind and to enter into the inner reality.
There are many different Yoga Paths and accordingly many different techniques of meditation. Here are some examples: Bhakti Yoga, the path of love, Karma Yoga, the path of selfless service, Jnana Yoga, the path of the mind. No path is the best one for everybody; each one has to select the path that fits his need best.