A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen,[1] the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.
For example, a 700 x 20 C road tire would be a 20-622; a 700 x 38 hybrid tire would be a 38-622. The width difference between these sizes would make them less-than ideal replacements for one another, but any rim that could fit one of them would work after a fashion with the other.
The numbers in the tire size refer to its width, aspect ratio, and wheel diameter. 205/55R16 means the tire is 205 mm wide, has an aspect ratio (that is, the width divided by the height) of 55%, and fits on a 16 rim.R means radial tire. They're all radials nowadays.