n. An optical device used to measure the diameters of fibres such as wool
the GNU version of the Collaborative International Dictionary of English
n. An instrument for measuring the diameters of minute particles or fibers, from the size of the colored rings produced by the diffraction of the light in which the objects are viewed.
The Century Dictionary and Cyclopedia
n. An optical instrument for measuring the diameters of minute particles and fibers from the size of the colored rings produced by the diffraction of the light in which the objects are viewed.