What is Community?

A long time ago when I was all keen (I still am) about being a Community Development Worker I decided to write on a whiteboard in the local youth club a simple question;
What is Community?

The answers varied a bit - 'It's to do with Ants', 'I dunno' and similar answers were written up on the board, but one young person in the youth club actually said 'It's about Us', which was the best answer that I had from the young people that night.

So now that you are all Trainee Community Workers I am going to ask you the same question;
What is Community? If you want to do a little research on the internet to find some definitions that is fine, but I would rather you all have a stab at it in your own words, a definition that you are comfortable with and can explain.

I also would like you too all look at your daily lifes and think about all of the 'different' communities that you are involved in and write a list for us all to see. Please leave your answers and lists in the comment section of this post.

P.S. If anyone else would like to also have a go at giving us a definition of Community then please do.