Shaftment

The shaftment is an obsolete unit of length defined since the 12th century as 6 inches, which nowadays is exactly 152.4 mm.

A shaftment was traditionally the width of the fist and outstretched thumb.

It occurs in Anglo-Saxon written records as early as 910 and in English as late as 1474.

It is derived from Old English sceaft, in turn from Proto-Germanic: *skaftaz ('shaft') and Old English mund, from the Proto-Germanic *mund, in turn from Proto-Indo-European: *man ('hand').

Two shaftments make a pes manualis (Latin for 'a foot fitted to the hand').