Mahāmudrā (Sanskrit; Tib. Chagchen, Wylie: phyag chen, contraction of Chagya Chenpo, Wylie: phyag rgya chen po) literally means "great seal" or "great symbol."
The commentator Kshemaraja of the Shivaistic Spanda Karika sees the origin of the Tibetan Mahamudra - Sadhana in a text which spread from Kashmir over the Krama school to Tibet and wass later practiced as adapted Mahamudra especially in the Kagyu.
In tibetan buddhism the name refers to a body of teachings representing the culmination of all the practices of the Sarma schools, who believe it to be the quintessential message of all of their sacred texts.
The mudra portion denotes that in an adept's experience of reality, each phenomenon appears vividly, and the maha portion refers to the fact that it is beyond concept, imagination, and projection.
The Mahamudra is a method of knowing the true nature of all things. This teaching is based on four levels of meditation practice, the so-called 'four yogas of Mahamudra' 
After the Drikung - Kagyu, the fivefold path of Mahamudra consists of: