Definition:General Logarithm/Common

Definition
When $a = 10$, logarithms base $a$ are referred to as common logarithms.

Before the advent of cheap means of electronic calculation, they used to be important.

In elementary textbooks and on most pocket calculators, $\log$ is assumed to mean $\log_{10}$. This ambiguous notation is not recommended, particularly since $\log$ often means base $e$ in more advanced textbooks.

Also known as
Common logarithms are sometimes referred to as Briggsian logarithms, for Henry Briggs.