form factor

1(physics) The ratio of the RMS value to the absolute mean of a sinusoidal wave (especially to that of an alternating current).
2(physics) Any of several functions that describe the unknown internal state of a particle.
3(physics) The emissivity of a material.
4(crystallography) A function that describes the scattering power of an atom as function of the scattering angle.
5(mechanics) A factor describing the stress distribution of a body.
6(engineering, design, commerce) The geometry of an object, especially in engineering design; configuration.