In a technical term, there is both small cells and large cells, but they are microscopic because they are what organic life is created upon. With cells, living creatures is possible. Cells are also small since there is such a large quantity of them, that they can be combined with other cells into a conglomerate that will synergize into a life form.
Also cells can be big, for example the egg cell within a female human can be as large as the head of a pin, which is absurdly large for a cell.
