value: the amount (of money or goods or services) that is considered to be a fair equivalent for something else
measure: how much there is or how many there are of something that you can quantify
planck's law: (physics) the basis of quantum theory; the energy of electromagnetic waves is contained in indivisible quanta that have to be radiated or absorbed as a whole; the magnitude is proportional to frequency where the constant of proportionality is given by Planck's constant