Words mean what I use them to mean. Dictionary definitions merely report how most people use words. They may not always report how I use them or how small groups of people use them. So any word can mean anything I use it to mean. The problem is that using words in some private sense that is unfamiliar to others will result in miscommunication. Because there is a shared understanding of how English people use words we must use them in the standard ways if we want to be understood. The word “nice” previously meant “stupid” and the word “gay” previously meant “happy,” but now they mean something different. That’s because how we use words evolves down through the centuries. There is Old- Middle- and Modern English, which was derived in part from German and even Greek forbearers. There is American, Britain, and Australian English.
Now let’s think about the word “atheism” in this light. I am an atheist. What do I mean when I use this word? I mean that I do not think there are any supernatural beings or supernatural forces. It’s not that I have no beliefs about them. I do. I believe they do not exist. People who do not have any beliefs about such beings are people who have never considered them in the first place.
By using this word in that way the ONLY question left unresolved is whether I am effectively communicating to others. The problem is that there is no agreed upon definition of this word by atheists themselves. One of the problems is that atheism is a negative word. Etymologically speaking an atheist is a non-theist (a=non theist). Christians themselves were called atheists in the Roman days because they did not believe in the Roman pantheon. But if I were to say that some object is not a door I have not told you what that object is, only what it is not. The problem is further compounded by Christians themselves who wish to define the word for us as meaning “metaphysical naturalists,” which may not adequately describe all of us in the future.
Skeptics have proposed other words to positively describe themselves as “Brights” or “Secular Humanists.” There are agnostic atheists, spiritual atheists, and Christian atheists. There is both a positive and negative atheism. Buddhism may be described as an atheistic philosophy.
For Christians listening in on these discussions let me say for the record that I consider them to be little more than Wittgensteinian language games, which will probably be solved in the future as more and more atheists adopt the same language to describe the same thing, which, when the dust settles will indeed communicate who we are and what we share (if there is a "we" to be found). [Keep in mind that Christians have the same problem with the word “Christian.” Is everyone a Christian who describes himself as one? I repeatedly hear that some group or person is/was not a “true Christian.”] I suspect that if most everyone in the world became atheists there wouldn't even be a word to describe us. We would probably be described as human beings, or members of the same golf club, or of another type grouping.
In any case, Dr. John Shook recently attempted to define it. See what you think.