A shape that is formed by groups of people on the dance floor of most nightclubs or anywhere dancing occurs. Usually consists primarily of women dancing with each other who are inherently hostile to outsiders and unwanted males. Attempts to broach a club circle by a male will often result in hostile looks or the women in question tightening up the circle, so as to give the intruder no room to dance and ultimately forcing them to go elsewhere. This is what is known as "closing the circle."
Club circles can contain men as well. Oftentimes these men are former pursuers of the women they are dancing with, only these men have been unfortunate enough to hit the friend zone. As such they are now regarded as sexually neutral by their female friends and have probably been brought to the club in order to serve as bodyguards against other males. Subsequently they tend to be very hostile towards males (their hostility stemming from repressed sexual frustration) and can also be very possessive and jealous. Cockblocking is also one of the activities they engage in.
Guy 1: Damn dude, I've been trying to get girls to dance with me for like twenty minutes and none of them are letting me in.
Guy 2: I know man. The club circles are really tight tonight.