The physical size of a device as measured by outside dimensions. With regard to a disk drive, the form factor is the diameter of the platters, such as 2.5", 3.5" and 5.25", not size in terms of ...

A common smartphone case design, which is thin and rectangular like the iPhone. Other form factors have two connected elements such as a "flipper," which unfolds to open, and a "slider," in which a ...