1a law stating that in fluorescence the wavelength of the emitted radiation is longer than that of the radiation causing it. This is not true in all cases.
2an expression describing the resisting force on a particle moving through a viscous fluid and showing that a maximum velocity is reached in such cases, e.g. for an object falling under gravity through a fluid.
late 19th century: named after Sir George Stokes (1819–1903), British physicist
Stokes' law in other Oxford dictionaries
Definition of Stokes' law in the US English dictionary