This Dictionary of Atheism provides more than 150 definitions of terms related to the subject of atheism, ranging from those of historic importance, including the history of the term atheist itself, to crucial concepts in the contemporary study of atheism, such as agnosticism and scepticism. Coverage includes secular and humanist organizations and publications, significant events in the history of atheism, such as the Scopes Monkey Trial, neologisms adopted by atheists including Bright and New Atheism, and parodic deities and religions such as Pastafarianism and the Flying Spaghetti Monster. Atheism is a growing subject of study with a significant scholarly presence emerging online, and many of the new terms covered represent the first authoritative definitions for this subject.