n. 1 one of a series of arithmetic exponents tabulated to simplify computation by making it possible to use addition and subtraction instead of multiplication and division. 2 the power to which a fixed number or base ( see BASE(1) 7) must be raised to produce a given number (the logarithm of 1000 to base 10 is 3). °Abbr.: log. common logarithm a logarithm to the base 10. natural (or Napierian) logarithm a logarithm to the base e (2.71828.....). °Abbr.: ln or log**. logarithmic adj. logarithmically adv.
[ mod.L logarithmus f. Gk logos reckoning, ratio + arithmos number ]