Unit Definition (centimeter)
The centimeter (or centimetre) was the basic unit of distance in the former CGS (centimeter, gram, second) version of the metric system, equal to 0.01 meter. The engineering standard uses every third power of ten, such as 10e3, 10e9, 10e12, etc., and for small numbers 10e-3, 10e-6, etc. The only exception is the centimeter. "Cent" means a hundredth, or 10e-2, but the centimeter is still commonly used because it is such a convenient unit for measuring length.

Unit Definition (palm [Britain, Roman minor])
A palm, when used as a unit of length, is usually four digits or three inches, i.e. 7.62 cm (for the international inch). The width of an adult human male palm is indeed about 10 centimetres.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (¼ palm), finger (7/24 palm), hand (4/3 palms), shaftment (2 palms), span (3 palms), cubit (6 palms) and ell (15 palms).