Dhyana is a type of meditation, like the other 2 last limbs of Patanjali’s Ashtanga yoga Dharana and Samadhi. It is used to describe a specific meditation based on simultaneous awareness and detachment from the environment and the body. The transcendence of this meditation is Samadhi, which is the ultimate bliss of the 8th limb of yoga. This is when the consciousness detached from the body, reaching a higher state of feeling and awareness. Samadhi is ultimately obtained in Savasana, which is why emphasis is based on the posture in most Indian school of yoga.
Dhyana has similar meanings in Jain, Hindu, and Buddhist traditions, meaning a focused meditation where one is aware of their surroundings, but detached from them as purely an observer. What does that mean? Essentially it means that the outside world has little influence upon the state of the practitioner. They are aware of the world, but uninfluenced by the fluctuations of the universe around them, fully detached and content with the internal sensations and peace that has been cultivate. This is an advanced state of meditation that Zen Buddhist have many practices for; this state is typically referred to as a precursor for Samadhi, or complete bliss.
In Buddhism, there are four levels of Dhyana, called the jhanas by the Sutta Pitaka, a Buddhist holy book, each of which increases the depth of meditation. Each level refers to a different state of meditative absorption where the practitioner is taken into a deep state of meditation, or an altered conscious state. Each focuses on creating more equanimity between thoughts and greater balance through destroying blockages in the thoughts. The jhanas are a set of meditative practices leading to increased serenity and are mentioned as the meditative exercises that the Buddha used underneath the bodhi tree and during the period where he taught about the eightfold path. Buddhists believe that a foundation of morality, proper conduct, and a removal of the five hindrances lead to the availability of the jhanas within meditation. One must scale the four jhanas in meditation in order to reach Samadhi, or the supreme state of bliss.
The Hindu definition of Dhyana is a bit different. Dhyana is the seventh limb of yoga and obtained after Dharana, or single pointed focus. This is the stage of awareness and detachment, simultaneously. The Dhyana meditational exercises are taken up to bring about increased self-knowledge, to assist in separate the maya (illusion) from reality to gain moksha, or liberation from Samsara. Dhyana is also a specific system that Sri Krishna gave to Arjuna within the Bhagavad Gita, being the fourth system of yoga after Karma, Jnana, and Bhakti yoga. In Dhyana, the meditator is not aware that they are meditating, but is only aware of existence. Dhyana comes after Dharana because the object of the senses becomes one with the meditator and not a separate object. This is a pure detachment from the physical world, leading to a relaxed concentration of the senses until the exercises of Jnana lead to Samadhi, or bliss.
Dharana is an integral part of the Samyama (the last 3 limbs of yoga), detaching the mind from its physical bindings in the world. The jnanas, or stages of Dhyana, are fairly elusive, but they build the serenity of the practitioner until thoughts are actually linked to reality. It could be inferred that this means that the constructive nature of the mind if let go to actually perceive reality for the first time, which then leads to the blissful state of Samadhi. Self-knowledge, it seems, are the last steps up the ladder of the 8 limbs of yoga.
The seventh limb of yoga is very interesting and quite complex; I expect traveling to India will give me new insights into how the exercises of Jnana and Dhyana can be completed to raise consciousness to the blissful state of Samadhi. Simultaneous awareness and detachment is powerful, using these concepts in your own yoga practice may change things quite a bit. Stay tuned for the final limb of yoga, Samadhi, the final step on the path to enlightenment.