In Britain, 15ᵗʰ – 20ᵗʰ centuries, various units all of which are 1/16ᵗʰ of some larger measure. The ratio probably comes from the Roman digitus, (literally, finger, and hence nail), having been 1/16ᵗʰ of a pes.


As a unit of length,

In England, (by far the most common meaning) = 2¼ inches, 1/16ᵗʰ of a yard.

In Scotland, 1/16ᵗʰ of the Scottish ell of 37 inches = 2 5/16 inches.¹

In Orkney, Scotland, the distance from the knuckle to the tip of the middle finger, “given as eight to a yard, i.e. 4½ inches”.²

1. Dictionary of the Older Scottish Tongue. Now enlarged and online at

2. Scottish National Dictionary (SND) Now enlarged and online at

s.v. nail, definition 3. This entry raises questions. The yard is not a Scottish unit, neither on the mainland nor Orkney. Why 1/8? Your present author speculates that this nail is 1/16th of the Norwegian favn. This is the same unit that Graham describes as a knuckle in his Shetland Dictionary.


As a unit of mass:

In Scotland, around 1400 for wool = 6 pounds, the pound being the wool pound of Bruges. This is 1/16ᵗʰ of the Bruges hundredweight of 96 pounds.1,2

In England around 1500 it begins to be used as a synonym for the clove, 7 pounds, 1/16ᵗʰ of a 112-pound hundredweight clickable chart symbol

1. Connor and Simpson,page 760.

2. Dictionary of the Older Scottish Tongue. (DOST) Now enlarged and online at

s.v. nail, definition 3a. Many usage citations, including Flemish examples from the Bute MS.



Nail, s. 'a nail of beef,' v. g. i. e. the weight of eight pounds; Suss.

John Ray.
A Collection of English Words Not Generally used, with their Significations and Original, in two Alphabetical Catalogues, the one Of such as are proper to tbe Northern, the other to the Southern Counties…. 2nd edition.
London: Printed for Christopher Wilkinson, 1691.
from the edition edited by W. W. Skeat for the English Dialect Society.
Reprinted Glossaries.
London: Trubner, 1873-1874.

Apparently in Sussex the nail was 8 pounds.


A unit of land area, = 1/16ᵗʰ of an acre

1. Edward Nicholson.
Men and Measures; a history of weights and measures, ancient and modern.
London : Smith, Elder & Co., 1912.

Page 90 or 91.

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