boundary condition are the conditions you impose on the contour, either it solid body or the limit of your domain. cell zones are "repartitions" of the conplessive computing domain. For example, if you want to simulate the turbulent flow on a profile, but do not want it to be all turbulent, then split into two the calculation domain, define an appropriate model (k-eps or k-omega, check the manual for this), then go on cell condition and select the first part of the domain and then spulci laminar. in this way fluent simulates a laminar flow in the first part of the domain and turbulent in the second.
analogally you can give a certain rotation to the current in the area.
