If a number, x, is expressed as a power of another number, y, if x = yn, then n is said to be the logarithm of x to base y. Common logarithms are to the base 10; natural or Napierian logarithms are to the base e, a mathematical constant.
[G. logos, word, ratio, + arithmos, number]
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Examples: glitazone, GI cocktail, etc.