Femtometer
A femtometer (fm) is a unit of length in the metric system, equal to one-quadrillionth of a meter (1 fm = 10⁻¹⁵ meters). It is also known as a fermi, named after the physicist Enrico Fermi. Femtometers are used to measure extremely small distances at the subatomic level, such as the size of protons, neutrons, and atomic nuclei. For example, the radius of a proton is about 0.84 femtometers. This unit is commonly used in nuclear physics and particle physics, but it's far too small for everyday measurements.
Ell
An ell is a historical unit of length that was commonly used in medieval Europe, especially for measuring textiles and cloth. Its length varied by region but was typically about 45 inches (approximately 1.143 meters).
The ell originated from the length of the arm or forearm and was often used by tailors and merchants to measure fabric. Different countries had their own versions—for example, the English ell was about 45 inches, while the Scottish ell was longer, around 37 inches.
Although obsolete today, the ell played an important role in trade and clothing production before standardized measurements became widespread.
Summary:
1 ell ≈ 45 inches (1.143 meters)
Used mainly for measuring cloth and textiles
Length varied by region and country
The ell is now largely of historical interest but reflects the origins of many modern measurement systems.
No conversions available for length.