An angstrom unit, also known as an angstrom or Å, represents a very small length of distance, equaling one ten-billionth of a meter. There are several other terms used to describe this unit of measurement. One synonym is the nanometer, which is slightly larger at one billionth of a meter. Another synonym is the picometer, which is one trillionth of a meter. Additionally, some scientists also use the term fermi, equivalent to one quadrillionth of a meter or 10 angstroms, while others may use the milli-angstrom, equal to one thousandth of an angstrom. Regardless of the specific synonym used, all of these measurements represent incredibly small distances that are essential in the world of science and engineering.