The Concise Oxford Dictionary of World Religions describes agnosticism as
a philosophical view that claims that it is not possible, neither in principle nor in fact,
to know God's nature or if he even exists. The word itself derives from the ancient
Greek language, meaning "to not know". Thomas Henry Huxley is considered as the
man who coined the term the most.
If you want to find out more about agnosticism please follow the link.
Bibliography:
Bowker, John. "Agnosticism." The Concise Oxford Dictionary of World Religions. 1997. Encyclopedia.com. 06 Oct. 2013 <http://www.encyclopedia.com>.