A crew is basically a bunch of mates who hang out together.
You may call yourselves a group, friends, click, clique, posse - it doesn't matter.
Being part of a group could affect the way you dress, the words you use and especially the music you listen to.
It doesn't matter if you've got a crew or not, it's just as cool to do your own thing.
These crews are just a taster of loads of different crews that exist in the UK.
But you can't always define crews by music, other things can bring people together too.
You could be a part of different crews and the music taste of some even overlap.