Meaning of MICROMETER in English

MICROMETER

I. noun Etymology: French micromètre, from micr- + -mètre -meter Date: 1670 an instrument used with a telescope or microscope for measuring minute distances, a caliper for making precise measurements that has a spindle moved by a finely threaded screw, II. noun Etymology: International Scientific Vocabulary micr- + 3meter Date: 1880 a unit of length equal to one millionth of a meter

Merriam Webster. Explanatory English dictionary Merriam Webster.      Толковый словарь английского языка Мерриам-Уэбстер.