A nail, as a unit of cloth measurement, is generally a sixteenth of a yard or 21⁄4 inches (5.715 cm).
[2][3][4] On the other hand, R D Connor, in The weights and measures of England (p 84) states that the nail was the 16th part of a Roman foot, i.e., digitus or finger, although he provides no reference to support this.
[6] An archaic usage of the term nail is as a sixteenth of a (long) hundredweight for mass, or 1 clove of 7 pound avoirdupois (3.175 kg).
Petruchio is concerned that Katharine's dress has too many frills, wonders what it will cost, and suspects that he has been cheated.
For reformation whereof, be it enacted That from and after the first day of April next coming every of the said cottons being sufficiently milled or thicked, clean scoured, well wrought and fully dried, shall weigh twenty-one pounds at the least and shall contain in length twenty-one goads, or twenty-goads at the least, and in breadth at the most three quarters of the yard, or within one nail of three quarters of the yard at the least: (2) And that every of the said frizes or rugs being thicked and fully dried shall weigh forty-four pounds at the least and shall contain in length betwixt thirty five-yards and thirty-seven yards, and shall contain in breadth at the most three quarters of the yard, or within one nail of three quarters at the least, and not to be strained upon the tentors above one nail in breadth.