Form factor refers to the linear dimensions and configuration of a device as distinguished from other measures of size (for example Gigabytes; a measure of storage size):
in computing, form factor is used to describe the size and format of PC motherboards (see AT, ATX, WTX, BTX), but also of hard drives, power supplies, cases, and add-in cards. The term can also be used refer to the shape of a housing or package or mechanical connection associated with a device or mechanism within the context of its interface with other devices or mechanisms, also in regards to a human interface.
in engineering, the form factor is the proportion of radiation leaving one surface which is intercepted by another surface. This meaning of form factor is used in radiative heat transfer , illumination engineering , and computer graphics.
