A thousandth of an inch is a derived unit of length. Equal to 0.001 inch, it is normally referred to as either a thou ( /ˈθaʊ/), a thousandth, or (particularly in the United States) a mil.
The plural of thou is also thou (thus one hundredth of an inch is "10 thou"), while the plural of mil is mils (thus "10 mils"). Both words come from roots meaning "1000": "thou" from the English "thousand", which is from the Germanic root for 1000, and "mil" from the Romance root for 1000.
Famous quotes containing the word thou:
“if thou slip thy troth and do not come at all.
As minutes in the clock do strike so call for death I shall:
To please both thy false heart, and rid myself from woe,
That rather had to die in troth than live forsaken so.”
—Unknown. The Lady Prayeth the Return of Her Lover Abiding on the Seas (l. 1922)