A micron, short for a micrometer, is one-millionth of a meter. This size is approximately equivalent to 0.00004 inches, which means there are approximately 25,000 microns in an inch.
An average human red blood cell is approximately 5 microns in diameter. The average diameter of human hair is roughly 0.0035 inches in diameter, which is equivalent to 75 microns.
The micron is symbolized by the Greek lowercase letter "mu." The abbreviation "micron" was initially used to distinguish the units of a tool used to measure small distances, also called a micrometer. In 1967, the International System of Units officially revoked the use of the term "micron" in favor of the standardized term "micrometer."