A measure of about six inches.

an old English unit of distance equal to 2 palms. A shaftment is the distance from the tip of the outstretched thumb to the opposite side of the palm of the hand. The ending "-ment" is from the old English word mund, hand. The shaftment was an important unit in Saxon England, where it was equal to about 16.5 centimeters (6.5 inches). After the modern foot came into use in the twelfth century, the shaftment was reinterpreted as exactly 1/2 foot or 6 inches (15.24 centimeters). The shaftment continued in common use through at least the fifteenth century, but it is now obsolete.

A shaftment, when used as a unit of length, is usually six inches or two palms, i.e. 15.24 cm (for the international inch). It is thought to be the distance from the tip of the outstretched thumb to the other side of the palm. In English this unit has mostly fallen out of use, as have others based on the human arm: digit (1/8 shaftment), finger (7/48 shaftment), palm (½ shaftment) hand (2/3 shaftment), span (1½ shaftments), cubit (3 shaftments) and ell (7½ shaftments).