logarithm

log·a·rithm

noun \ˈlȯ-gə-ˌri-thəm, ˈlä-\

Definition of LOGARITHM

: the exponent that indicates the power to which a base number is raised to produce a given number <the logarithm of 100 to the base 10 is 2>

— log·a·rith·mic \ˌlȯ-gə-ˈrith-mik, ˌlä-\ adjective

— log·a·rith·mi·cal·ly \-mi-k(ə-)lē\ adverb

Origin of LOGARITHM

New Latin logarithmus, from log- + Greek arithmos number — more at arithmetic

First Known Use: circa 1616

Other Mathematics and Statistics Terms

abscissa, denominator, divisor, equilateral, exponent, hypotenuse, oblique, radii, rhomb

logarithm

noun    (Concise Encyclopedia)

In mathematics, the power to which a base must be raised to yield a given number (e.g., the logarithm to the base 3 of 9, or log 9, is 2, because 3² = 9). A common logarithm is a logarithm to the base 10. Thus, the common logarithm of 100 (log 100) is 2, because 10² = 100. Logarithms to the base e, in which e = 2.71828…, called natural logarithms (ln), are especially useful in calculus. Logarithms were invented to simplify cumbersome calculations, since exponents can be added or subtracted to multiply or divide their bases. These processes have been further simplified by the incorporation of logarithmic functions into digital calculators and computers. See also John Napier.