Logarithms are a way of expressing powers.
The logarithm for a base and a number is defined to be the inverse function of taking to the power , i.e., .¹
The simplest way to explain the concept of logarithms is through an example:
The subscript of the logarithm above denotes the base of the logarithm. This is equivalent to the number which is raised to a power in the preceding equation. The logarithm to the base 2 of 32 is 5, because 2 to the power of 5 is 32.
¹ Weisstein, Eric W. “Logarithm.” From MathWorld–A Wolfram Web Resource. http://mathworld.wolfram.com/Logarithm.html