A clique is just that. It's a way for you to define a smaller audience amongst your friends who share something in common.

Maybe 5 of your friends play on the same soccer team, or maybe 3 of your friends work at the same company,

or maybe 7 of your buddies go for beers and wings every Monday night.

Cliques help you manage your audience so that you can send plurks to only the friends who need to be notified.

Thank you, miss silver!

So, it's a Group. Or in LJ terms, a filter.

LiveJournal, which is very good at letting you subdivide your friendslist.

*curtsies*