Overview of differences between Cartesian and Delta style printers.
Cartesian printers move the nozzle in X, Y and Z planes, with various designs having a the nozzle move in X-Y plane with bed on Z plane or with bed moving in Y-Z plane while the nozzle moves in X plane.

Delta style printers, called because they are based in typical pick and pack delta style robots where the bed is fixed but the printer head moves in XYZ planes.

Via Cartesian Vs. Delta Printers: How Do They Work? – PrintSpace : PrintSpace.