I. mi ‧ crom ‧ e ‧ ter /maɪˈkrɒmətə, maɪˈkrɒmɪtə $ -ˈkrɑːmətər/ BrE AmE noun [countable]
an instrument for measuring very small distances
II. mi ‧ crom ‧ e ‧ tre BrE AmE British English , micrometer American English /ˈmaɪkrəʊˌmiːtə $ -kroʊˌmiːtər/ ( also mi‧cron /ˈmaɪkrɒn $ -krɑːn/) noun [countable]
[ Date: 1800-1900 ; Language: Modern Latin ; Origin: Greek , from mikros 'small' ]
a unit for measuring length. There are one million micrometres in one metre.