Static balance is single plane (or a correction at a single point), for example: a wheel put on a bearing assembly and let to freely orient itself. Thus the heaviest part will naturally rotate to the bottom. This is typically checked a few times to insure the correct heavy point. To correct, weight is added 180 degrees opposite the heavy spot.

Dynamic balance is dual plane (or a correction at two points), for example: a spinning wheel on a dynamic balancer. Typically their will be two heavy points (one on each side of the wheel. Weights are added opposite of each heavy point. Dynamic balance also accounts for static balance.

So neutral balance is just a generic term for balancing something close to zero (or whatever the tolerance is).