lg

Etymology
Abbreviation of.

Symbol

 * 1)  binary logarithm; logarithm to the base 2.
 * $$\lg(x) = \log_{2}(x)$$. $$ \lg(2) = 1 $$
 * 1)  base 10 logarithm
 * $$\lg(x) = \log_{10}(x)$$. $$ \lg(10) = 1 $$
 * $$\lg(x) = \log_{10}(x)$$. $$ \lg(10) = 1 $$

Usage notes
This symbol, lg, is defined as the base 10 logarithm in the ISO 80000-2:2019 standard, which instead prescribes the symbol for the binary logarithm. Despite this, lg is not widely used in English-language literature. Wolfram MathWorld observes that the use of lg for a base 10 logarithm is standard in German and Russian literature.