logarithm

/ˈlɑɡəˌrɪðəm/

Other forms: logarithms

A logarithm is a mathematical concept involving multiplication. A logarithm is the exponent that will yield a certain number. For a base of 3 to produce 9, the logarithm would be 2.

Every number has a logarithm that — if it were an exponent — would produce a certain number. For example, let's say the base is 5. The logarithm to produce 25 would be 2, because 5 times 5 is 25. If the base is 10, the logarithm to produce 10000 would be 4. The logarithm is also called the log. Scottish mathematician John Napier coined the word by using the Greek logos for "word or ratio” plus arithmos for "number.”

Definitions of logarithm

1. noun

   the exponent required to produce a given number
   synonyms: log

   types:

   common logarithm

   a logarithm to the base 10

   Napierian logarithm, natural logarithm

   a logarithm to the base e

   type of:

   exponent, index, power

   a mathematical notation indicating the number of times a quantity is multiplied by itself