Oxford Dictionaries define agnostic (1):
A person who believes that nothing is known or can be known of the existence or nature of God or of anything beyond material phenomena; a person who claims neither faith nor disbelief in God.
Philosophy in Figures
Philosophy in Figures Ryan Reece explains the above diagram:
(1) Oxford Dictionaries – agnostic https://en.oxforddictionaries.com/definition/us/agnostic
(2) Philosophy in Figures http://philosophy-in-figures.tumblr.com/post/88206026601/atheism-vs-agnosticism (accessed 12th September 2017)
(3) Philosophy in Figures http://disq.us/p/p9ed2j (accessed 12th September 2017)