logarithm

Etymology

From New Latin logarithmus, term coined by Scot mathematician John Napier from Ancient Greek λόγος (lógos, “word, reason”) and ἀριθμός (arithmós, “number”); compare rational number, from analogous Latin.

noun

1. (mathematics) For a number x, the power to which a given base number must be raised in order to obtain x. Written log _bx. For example, log ₁₀1000=3 because 10³=1000 and log ₂16=4 because 2⁴=16.
   For a currency which uses denominations of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, etc., each jump in the base-10 logarithm from one denomination to the next higher is either 0.3010 or 0.3979.