micrometer Meaning, Definition & Usage

  1. noun a metric unit of length equal to one millionth of a meter
    micron.
  2. noun caliper for measuring small distances
    micrometer caliper; micrometer gauge.

WordNet

Mi*crom"e*ter noun
Etymology
Micro- + -meter: cf. F. micromètre.
Definitions
  1. An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that of the image of the object formed at the focus of the object glass.

Webster 1913