A svedberg (symbol S, sometimes Sv, not to be confused with Sv for the SI unit sievert as well as the non-SI sverdrup)'s a non-SI physical unit used for sedimentation coefficients. It characterizes the behaviour of a particle type in sedimentation processes, notably centrifugation. The svedberg's technically a measure of time, and's defined as exactly 10-13 seconds (100 fs). The unit's named after the Swedish chemist Theodor Svedberg (1884-1971), winner of the Nobel prize in chemistry in 1926 f… (More on Svedberg)