DictionarythouSmall unit of length
noun

thou

One thousandth of an inch.

The mechanic measures a gap of five thou.

Etymology

Thou is a shortening of thousandth. Engineering uses it for one thousandth of an inch.

More examples

  • The drawing specifies a tolerance of one thou.
  • She removed two thou from the surface.
  • The instrument reads thickness in thou.

Forms

thou

Similar words

mil
A common American term for a thousandth of an inch.