Originally Posted by prathmann

No, it is certainly not referring to 700 centimeters - that would be almost 23 feet. 700c rims actually have a diameter measured at the bead of 622 millimeters, but the 700 referred to the approximate total diameter at the edge of the tire being about 700 millimeters. As I stated before, there used to be several different widths of rims designated as 700a, 700b, 700c, and 700d all of which had about the same diameter of tire when used with tires of appropriate width for the respective rim (narrowest for 700a, widest for 700d). Presumably the 700c rims were designed for tires with a width of about 39mm so the diameter of the tire edge would come out as 622mm + 2 x 39mm = 700mm.