Thou

The title of this article is ambiguous. Further meanings are listed under Thou (disambiguation) .

Thou (abbreviation for thousandth of an inch ) is a measure of length in the Anglo-American system of measurement and the English name for the American measure of length mil (from Latin millesimus ). 1 Thou is a thousandth of an inch , so it corresponds to 25.4  µm .

Thou is often used for concentricity measurements, the synonymous mil for dimensions of electronic components , when designing printed circuit boards and for specifying the thickness of foils and coatings. The unit mil is also used in connection with mechanical oscillations and vibrations.