S: (n) coefficient (a constant number that serves as a measure of some property or characteristic)
S: (n) absorption coefficient, coefficient of absorption, absorptance (a measure of the rate of decrease in the intensity of electromagnetic radiation (as light) as it passes through a given substance; the fraction of incident radiant energy absorbed per unit mass or thickness of an absorber) "absorptance equals 1 minus transmittance"
S: (n) coefficient of friction (the ratio of the weight of an object being moved along a surface and the force that maintains contact between the object and the surface)
S: (n) coefficient of mutual induction, mutual inductance (a measure of the induction between two circuits; the ratio of the electromotive force in a circuit to the corresponding change of current in a neighboring circuit; usually measured in henries)