PALM (UNIT)

A 'palm', when used as a unit of length, is usually four digits (''fingers'') or three inches, i.e. 7.62 cm (for the international inch).
In English this unit has mostly fallen out of use, as have 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).