I've been dealing with the concept of moment this whole year, in statics/dynamics but I've never really completely understood it, just rather memorized it. What I think moment is: If some point on a body has moment, then this means it wants to rotate. So moment is essentially what causes rotation. But here is something that I'm confused about: Pins allow rotation, so they have zero moment. That is what confuses me. I understand that pins don't resist moment, so there is no unknown moment about a pin. But according to my above definition of moment, if the moment at the point of the pin is zero then this means it will not rotate? But pins are supposed to allow rotation?