Definition of logarithm in English:

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Pronunciation: /ˈlɒɡərɪð(ə)m/
(abbreviation log)


A quantity representing the power to which a fixed number (the base) must be raised to produce a given number: proportional to the logarithm to the base 10 of the concentration
More example sentences
  • We can use arithmetics with different bases, fractions, decimals, logarithms, powers, or simply words.
  • Other examples are negative numbers, complex numbers, trigonometry, raising to powers, logarithms, and the beginnings of calculus.
  • It was a 17th century Scottish baron, John Napier, who first discovered the power of the logarithm as an important function in mathematics.

Logarithms can be used to simplify calculations, as the addition and subtraction of logarithms is equivalent to multiplication and division, though the use of printed tables of logarithms for this has declined with the spread of electronic calculators. They also allow a geometric relationship to be represented conveniently by a straight line. The base of a common logarithm is 10, and that of a natural logarithm is the number e (2.71828 ...).


Early 17th century: from modern Latin logarithmus, from Greek logos 'reckoning, ratio' + arithmos 'number'.

For editors and proofreaders

Line breaks: loga|rithm

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