A convenient unit of length for measuring nuclear sizes is the femtometre (fm), which equals 10−15 metre.
The basic Babylonian unit of length was the kus (about 530 mm, or 20.9 inches), also called the Babylonian cubit.
Angstrom, unit of length used chiefly in measuring wavelengths of light, equal to 10−10 metre, or 0.1 nanometer.
A convenient unit of length for measuring atomic sizes is the angstrom, defined as 10−10 metre.
The rest of the world rightly laughs at the all-powerful Americans who still base their unit of length on the bottoms of men's feet.
Furlong, old English unit of length, based on the length of an average plowed furrow (hence "furrow-long," or furlong) in the English open- or common-field system.
Since the measurement of angles is absolute, independent of any convention concerning the selection of units, it follows that an absolute unit of length exists.
Millimetre (mm), also spelled millimeter, unit of length equal to 0.001 metre in the metric system and the equivalent of 0.03937 inch.
Based on the chi, a unit of length after 1860 measuring 14.1 inches, the mou has been defined by customs treaty as 920.417 square yards.
Yard, Unit of length equal to 36 inches, or 3 feet (see foot), in the U.S. Customary System or 0.9144 metre in the International System of Units.
Kilometre (km), also spelled kilometer, unit of length equal to 1,000 metres and the equivalent of 0.6214 mile (see metric system).
