logarithm

[ law-guh-rith-uhm, -rith-, log-uh- ]

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).

logarithm

/ ˈlɒɡəˌrɪðəm /

noun

1. See natural logarithm, common logarithm
   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 log aM ) is x Often shortened tolog See also common logarithm natural logarithm

logarithm

/ lô′gə-rĭth′əm /

1. 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 log 10 1,000) is 3 because 10 ³ = 1,000.
2. See more at common logarithm

Word History and Origins

Origin of logarithm¹

1605–15; < New Latin logarithmus < Greek lóg ( os ) log- + arithmós number; arithmetic

Word History and Origins

Origin of logarithm¹

C17: from New Latin logarithmus, coined 1614 by John Napier , from Greek logos ratio, reckoning + arithmos number

Example Sentences

In 1614 John Napier had invented logarithms, showing how multiplication could be accomplished by addition.

From Science News

FiveThirtyEight’s urbanization index is calculated as the natural logarithm of the average number of people living within a five-mile radius of a given resident.

From FiveThirtyEight

This quantity is defined as the logarithm of a matrix — an array of numbers.

From Quanta Magazine

The new formula relies on the mathematical concept known as logarithms.

From Science News For Students

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

From Project Gutenberg

The logarithm of the number is then obtained by adding the previously calculated logarithms of the factors.

From Project Gutenberg

What is the probability that the fifth decimal of a logarithm taken at random from a table is a '9'?

From Project Gutenberg

We can calculate our logarithm without recourse to the table, but we do not wish to give ourselves the trouble.

From Project Gutenberg

In July, while at work on logarithm tables, he was overtaken by a sudden fainting fit, evidently of an epileptic nature.

From Project Gutenberg