Definition of millimetric in US English:

millimetric

adjective

  • 1Of the order of a millimetre in length or thickness; relating to or employing electromagnetic radiation having a wavelength of 1 to 10 millimetres; measured or expressed in millimetres.

  • 2Generally. As small as a millimetre (in figurative contexts); (of a distinction) very fine; (of accuracy) extreme. rare.

Origin

Late 19th century; earliest use found in Appletons' Journal. From millimetre + -ic, after metric.

Pronunciation

millimetric

/ˌmɪlɪˈmɛtrɪk/