consider the example here
Pixel size of image and raster data—ArcGIS Pro | Documentation
4m x 4m cells
5 cells
area covered = 16 * 5 == 80 m^2
cell size refers to one direction since they are both equal in width and height, the area is cell size * cell size.
some raster formats exist where the width and height are different and both need to be specified
... sort of retired...
