The original Greek word 'gnosis', is "to know" or knowledge in terms of being 'acquainted with' God. Gnosis therefore, is commonly referred to as the "direct knowledge of the divine mysteries". Gnosticism is an exploration of the spiritual and esoteric paths that encompasses many traditions of "knowing" the depth of the mysteries of our beingness. This knoweldge is based in deeper more sacred, inner spiritual truths derived from direct experience. Gnosis is the path of initiation into the Greater Mysteries and is the heart of all the great religions. In a specific religious sense is it the knowledge of God. Gnosis is the ultimate Revelation of knowing (versus reasoning) that is bestowed by the Divine -when God reveals hisself to man. Source: Starstuffs
Gnosis is the common Greek noun for knowledge. In the context of the English language gnosis generally refers to the word's meaning within the spheres of Christian mysticism, Mystery religions and Gnosticism where it signifies 'spiritual knowledge' in the sense of mystical enlightenment.
Gnosis in Greek Orthodox thought is the spiritual knowledge of a saint (one who has obtained theosis) or mystically enlightened human being. Within the cultures of the term's provenance (Byzantine and Hellenic) Gnosis was a knowledge or insight into the infinite, divine and uncreated in all and above all, rather than knowledge strictly into the finite, natural or material world. Gnosis is a transcendental as well as mature understanding. It indicates direct spiritual experiential knowledge and intuitive knowledge, mystic rather than that from rational or reasoned thinking. Gnosis itself is obtained through understanding at which one can arrive via inner experience or contemplation such as an internal epiphany of intuition and external epiphany such as the Theophany. Source: Wikipedia