If you want to be specific about what most of the internet refers to as 'Anonymous', it is /b/ on 4chan. /b/ and their very odd lingo is relatively well organized, but anonymous amongst eachother. Collectively, they are what the majority of people refer to as the 'hacker collective anonymous'. They also refer to themselves as btards look it up on urbandictionary or (NSFW) encyclopedia dramatica to learn more.