A logarithm tells what exponent (or power) is needed to make a certain number, so logarithms are the inverse (opposite) of exponentiation. Just as an exponential function has three parts, a logarithm has three parts. The three parts of a logarithm are a base, an argument (also called power) and an answer.
A logarithm is a mathematical operation that determines how many times a certain number, called the base, is multiplied by itself to reach another number. ... Logarithms even describe how humans instinctively think about numbers.