If a number, x, is expressed as a power of another number, y, i.e., if x = yn, then n is said to be the l. 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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log·a·rithm (logґə-rith-əm) the power to which a number, fixed for a given system and usually called the base number, must be raised to obtain a second number. Logarithms are usually computed in the natural base e>, and are denoted loge> (also expressed ln). For example, if loge> (y) = x then e>x = y. See also e>.Medical dictionary. 2011.