# logarithm

[law-guh-rith-uh m, -rith-, log-uh-] /ˈlɔ gəˌrɪð əm, -ˌrɪθ-, ˈlɒg ə-/
noun, Mathematics.
1.
the exponent of the power to which a base number must be raised to equal a given number; log:
2 is the logarithm of 100 to the base 10 (2 = log10 100).
Origin of logarithm
1605-1615
1605-15; < New Latin logarithmus < Greek lóg(os) log- + arithmós number; see arithmetic
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Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for logarithm
Historical Examples
• For example, suppose the logarithm of 543839 required to twelve places.

• The complement of the logarithm of a sine, tangent, or secant.

William Henry Smyth
• As well might Lamartine sing his odes with the aid of the logarithm tables.

Frdric Bastiat
• That was short for logarithm, you know, because I was such a log at arithmetic.

F. Marion Crawford
• I always thought you were a sort of calculating machine, who slept on a logarithm table.

Arthur Train
• If the characteristic of a logarithm is negative, Oughtred indicates this fact by placing the - above the characteristic.

Florian Cajori
• As Fechner states it, 'Sensation varies, not as the stimulus, but as the logarithm of the stimulus.'

George John Romanes
• The integral part of a logarithm is called the index or characteristic, and the fractional part the mantissa.

• Hence the figure after the PH indicates the logarithm of the number of times the solution is diluted.

• The calculation of a logarithm can be performed by successive divisions; evolution requires special methods.

British Dictionary definitions for logarithm

## logarithm

/ˈlɒɡəˌrɪðəm/
noun
1.
the exponent indicating the power to which a fixed number, the base, must be raised to obtain a given number or variable. It is used esp to simplify multiplication and division: if ax = M, then the logarithm of M to the base a (written logaM) is x Often shortened to log See also common logarithm, natural logarithm
Word Origin
C17: from New Latin logarithmus, coined 1614 by John Napier, from Greek logos ratio, reckoning + arithmos number
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for logarithm
n.

1610s, Modern Latin logarithmus, coined by Scottish mathematician John Napier (1550-1617), literally "ratio-number," from Greek logos "proportion, ratio, word" (see logos) + arithmos "number" (see arithmetic).

Online Etymology Dictionary, © 2010 Douglas Harper
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logarithm in Science
 logarithm   (lô'gə-rĭ'əm)    The power to which a base must be raised to produce a given number. For example, if the base is 10, then the logarithm of 1,000 (written log 1,000 or log10 1,000) is 3 because 103 = 1,000. See more at common logarithm, natural logarithm.
The American Heritage® Science Dictionary