natural logarithm

American  

noun

Mathematics.

1. a logarithm having e as a base. ln

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natural logarithm British  

noun

1. Also called: Napierian logarithm.  a logarithm to the base e. Usually written log e or ln Compare e common logarithm

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natural logarithm Scientific  

1. A logarithm using base e. Natural logarithms are common in mathematics, especially in cases involving complex numbers. They are also called Napierian logarithms, after their inventor, English mathematician John Napier (1550–1617).

2. See more at e Compare common logarithm

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Etymology

Origin of natural logarithm

First recorded in 1810–20

Example Sentences

Here’s the conversion formula the scientists came up with: Human age is equal to 16 multiplied by the natural logarithm of the dog’s age, plus 31.

From Seattle Times

To calculate dog years, you must now multiply the natural logarithm of a dog’s age in human years by 16 and then add 31.

From New York Times

A more accurate conversion isn’t so easy to do in your head: Multiply the natural logarithm of the dog’s age by 16, then add 31.

From Washington Post

In maths, ln refers to the natural logarithm of a number.

From The Guardian

Momentum conservation implies that the terminal speed of the rocket is given by this exhaust speed times the natural logarithm of the ratio between the initial and final mass of the rocket.

From Scientific American