Luminosity
The hit number is the number of time a word has been requested since a given date. It is somewhat similar to word usage frequency, but without considering the total number of hits (so it is not a frequency).
The luminosity is the log (base 10) of the hit number.
Luminescence
The herited hit number of a word meaning is the realtive part of the luminosity it receive from the word. A common meaning will inherit more luminostity than a rare one.
The luminescence of a word meaning is the log (base 10) of the herited hit number.