Hmmm such as simple question with no simple answer like so many words I understand what a side is I know it when I seen a side but I can not come up with a simple definition Merriam Webster has roughly 25 definitions of side see here I suppose definition number 2 is most applicable 2 a place space or direction with respect to a center or to a line of division as of an aisle river or street I do not think that it needs to be defined in the article Most English speakers will understand it Those that can not we can and do provide pictures and examples Do we need better pictures