Palm (unit)

anthropic unit of length, based on the width of the human palm and then variously standardized

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).

Three archaic hand units of measurment:
1: Hand = 4 inches = 10.16 cm
2: Span = 9 inches = 22.86 cm
3: Palm = 3 inches = 7.62 cm

In English this unit is no longer in use as other units that are 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).